The charge carrier concentration profile is a critical factor that determines semiconducting material properties and device performance.Dielectric force microscopy(DFM)has been previously developed to map charge carri...The charge carrier concentration profile is a critical factor that determines semiconducting material properties and device performance.Dielectric force microscopy(DFM)has been previously developed to map charge carrier concentrations with nanometer-scale spatial resolution.However,it is challenging to quantitatively obtain the charge carrier concentration,since the dielectric force is also affected by the mobility.Here,we quantitative measured the charge carrier concentration at the saturation mobility regime via the rectification effect-dependent gating ratio of DFM.By measuring a series of n-type GaAs and GaN thin films with mobility in the saturation regime,we confirmed the decreased DFM-measured gating ratio with increasing electron concentration.Combined with numerical simulation to calibrate the tip–sample geometry-induced systematic error,the quantitative correlation between the DFM-measured gating ratio and the electron concentration has been established,where the extracted electron concentration presents high accuracy in the range of 4×10^(16)–1×10^(18)cm^(-3).We expect the quantitative DFM to find broad applications in characterizing the charge carrier transport properties of various semiconducting materials and devices.展开更多
Intrinsic carrier concentration(ni) is one of the most important physical parameters for understanding the physics of strained Si and Si1-xGex materials as well as for evaluating the electrical properties of Si-based ...Intrinsic carrier concentration(ni) is one of the most important physical parameters for understanding the physics of strained Si and Si1-xGex materials as well as for evaluating the electrical properties of Si-based strained devices. Up to now, the report on quantitative results of intrinsic carrier concentration in strained Si and Si1-xGex materials has been still lacking. In this paper, by analyzing the band structure of strained Si and Si1-xGex materials, both the effective densities of the state near the top of valence band and the bottom of conduction band( Nc and Nv) at 218, 330 and 393 K and the intrinsic carrier concentration related to Ge fraction(x) at 300 K were systematically studied within the framework of KP theory and semiconductor physics. It is found that the intrinsic carrier concentration in strained Si(001) and Si1-xGex(001) and(101) materials at 300 K increases significantly with increasing Ge fraction(x), which provides valuable references to understand the Sibased strained device physics and design.展开更多
Sandwich-style memristor devices were synthesized by electrochemical deposition with a ZnO film serving as the active layer between Al-doped ZnO (AZO) and Au electrodes. The carrier concentration of the ZnO films is...Sandwich-style memristor devices were synthesized by electrochemical deposition with a ZnO film serving as the active layer between Al-doped ZnO (AZO) and Au electrodes. The carrier concentration of the ZnO films is controlled by adding HNO3 during the growth process. A resulting increase in carrier concentration from 10^17 to 10^19 cm^-3 was observed, along with a corresponding drop in the on--off ratio from 6,437% to 100%. The resistive switching characteristics completely disappeared when the carrier concentration was above 1029 cm-3, making it unsuitable for a memory device. The decreasing switching ratio is attributed to a reduction in the driving force for oxygen vacancy drift. Systematic analysis of the migration of oxygen vacancies is presented, including the concentration gradient and electrical potential gradient. Such oxygen vacancy migration dynamics provide insight into the mechanisms of the oxygen vacancy drift and provide valuable information for industrial production of memristor devices.展开更多
Possessing inherently low thermal conductivity,BiSbSe_(3) is a promising thermoelectric material for medium temperature.Therefore,to substantially optimize the thermoelectric performance of BiSbSe_(3),researchers main...Possessing inherently low thermal conductivity,BiSbSe_(3) is a promising thermoelectric material for medium temperature.Therefore,to substantially optimize the thermoelectric performance of BiSbSe_(3),researchers mainly focus on the strategies to improve its electrical transport properties.Among these strongly coupled thermoelectric parameters,carrier concentration and effective mass are two intrinsic variables to decisively affect the electrical transport properties.In this work,Cl as a donor dopant is effective to provide extra electrons in n-type BiSbSe_(3),and the carrier concentration and effective mass can be well optimized simultaneously with increasing Cl content owing to the multiple conduction bands in BiSbSe_(3).What’s more,maximum weighted mobility~53 cm^(2)V^(-1)s^(-1)is obtained in Cl-doped BiSbSe_(3),which contributes to a largely enhanced power factor~4.8μW cm^(-1)K^(-2)at room temperature and outperforms other halogen-doped BiSbSe_(3) samples.Finally,combining the significantly enhanced power factor and maintained low thermal conductivity,a maximum ZT~1.0 is achieved in Cl-doped BiSbSe_(3) at 800 K.展开更多
This study proposed a strategy for effectively diminishing the carrier concentration in Cu_(2)Te by introducing graphene sheets,Based on thermoelectric property measurements and single parabolic band modeling,the inco...This study proposed a strategy for effectively diminishing the carrier concentration in Cu_(2)Te by introducing graphene sheets,Based on thermoelectric property measurements and single parabolic band modeling,the incorporated graphene effectively reduced the carrier concentration,not only enhancing the thermoelectric performance of the Cu_(2)Te/graphene composite but also substantially improving its figure of merit up to ~1.47 at 1000 K,which is 268% higher than that of pristine Cu_(2)Te,This study gives an insight into the control of carrier concentration and thermoelectric properties in Cu_(2)Te,and it could be extended to other copper chalcogenides for excellent thermoelectrics.展开更多
All-solid-state fluoride ion batteries(FIBs)have been recently considered as a post-lithium-ion battery system due to their high safety and high energy density.Just like all solid-state lithium batteries,the key to th...All-solid-state fluoride ion batteries(FIBs)have been recently considered as a post-lithium-ion battery system due to their high safety and high energy density.Just like all solid-state lithium batteries,the key to the development of FIBs lies in room-temperature electrolytes with high ionic conductivity.β-KSbF_(4) is a kind of promising solid-state electrolyte for FIBs owing to its rational ionic conductivity and relatively wide electrochemical stability window at room temperature.However,the previous synthesis routes ofβ-KSbF_(4) required the use of highly toxic hydrofluoric acid and the ionic conductivity of as-prepared product needs to be further improved.Herein,the β-KSbF_(4) sample with an ionic conductivity of 1.04×10^(-4)s cm^(-1)(30°C)is synthesized through the simple solid-state route.In order to account for the high ionic conductivity of the as-synthesizedβ-KSbF_(4),X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive X-ray spectroscopy(EDS)are used to characterize the physic-ochemical properties.The results show that the as-synthesizedβ-KSbF_(4) exhibits higher carrier concentra-tion of 1.0×10^(-6)S cm-Hz^(-1)K and hopping frequency of 1.31×10^(6)Hz at 30°C due to the formation of the fluorine vacancies.Meanwhile,the hopping frequency shows the same trend as the changes of ionic conductivity with the changes of temperature,while the carrier concentration is found to be almost con-stant.The two different trends indicate the hopping frequency is mainly responsible for the ionic conduc-tion behavior withinβ-KSbF_(4).Furthermore,the all-solid-state FIBs,in which Ag and Pb+PbF_(2) are adopted as cathode and anode,andβ-KSbF_(4) as fluoride ion conductor,are capable of reversible charge and discharge.The assembled FIBs show a discharge capacity of 108.4 mA h g^(-1) at 1st cycle and 74.2 mA h g^(-1) at 50th cycle.Based on an examination of the capacity decay mechanism,it has been found that deterioration of the electrolyte/electrode interface is an important reason for hindering the commer-cial application of FIBs.Hence,the in-depth comprehension of the ion transport characteristics inβ-KSbF_(4) and the interpretation of the capacity fading mechanism will be conducive to promoting development of high-performanceFIBs.展开更多
AgCrSe2-based compounds have attracted much attention as an environmentally friendly thermoelectric material in recent years due to the intriguing liquid-like properties.However,the ultra-low carrier concentration and...AgCrSe2-based compounds have attracted much attention as an environmentally friendly thermoelectric material in recent years due to the intriguing liquid-like properties.However,the ultra-low carrier concentration and the high Ag_(Cr)deep-level defects limit the overall thermoelectric performance.Here,we successfully introduced Pb into Ag-deficient Ag_(0.97)CrSe_(2) alloys to tune the carrier concentration across a broad temperature range.The Pb^(2+) as an acceptor dopant preferentially occupies Cr sites,boosting the hole carrier concentration to 1.77×10^(19) cm^(-3) at room temperature.Furthermore,the Pb strongly inhibits the creation of intrinsic Ag_(Cr) defects,weakens the increased thermal excited ionization with the increasing temperature and slowed the rising trend of the carrier concentration.The designed carrier concentration matches the theoretically predicted optimized one over the entire temperature range,leading to a remarkable enhancement in power factor,especially the maximum power factor of ~500 μW·m^(-1)·K^(-2) at 750 K is superior to most previous results.Additionally,the abundant point defects promote phonon scattering,thus reducing the lattice thermal conductivity.As a result,the maximum figure of merit zT(~0.51 at 750 K) is achieved in Ag_(0.97)Cr_(0.995)Pb_(0.005)Se_(2).This work confirms the feasibility of manipulating deep-level defects to achieve temperature-dependent optimal carrier concentration and provides a valuable guidance for other thermoelectric materials.展开更多
Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg...Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg_(3)Sb_(2)remains lower than 1,which is mainly attributed to its inferior electrical properties.Herein,we synergistically optimize the thermoelectric properties of p-type Mg_(3)Sb_(2)materials via codoping of Cd and Ag,which were synthesized by high-energy ball milling combined with hot pressing.It is found that Cd doping not only increases the carrier mobility of p-type Mg_(3)Sb_(2),but also diminishes its thermal conductivity(κ_(tot)),with Mg_(2.85)Cd_(0.5)Sb_(2)achieving a lowκtot value of∼0.67 W m^(−1)K^(−1)at room temperature.Further Ag doping elevates the carrier concentration,so that the power factor is optimized over the entire temperature range.Eventually,a peak zT of∼0.75 at 773 K and an excellent average zT of∼0.41 over 300−773 K are obtained in Mg_(2.82)Ag_(0.03)Cd_(0.5)Sb_(2),which are∼240%and∼490%higher than those of pristine Mg_(3.4)Sb_(2),respectively.This study provides an effective pathway to synergistically improve the thermoelectric performance of p-type Mg_(3)Sb_(2)by codoping Cd and Ag,which is beneficial to the future applications of Mg_(3)Sb_(2)-based thermoelectric materials.展开更多
Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of...Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.展开更多
The Zintl compound Mg3Sb2 has been recently identified as promising thermoelectric material owing to its high thermoelectric performance and cost-effective,nontoxicity and environment friendly characteristics.However,...The Zintl compound Mg3Sb2 has been recently identified as promising thermoelectric material owing to its high thermoelectric performance and cost-effective,nontoxicity and environment friendly characteristics.However,the intrinsically p-type Mg3Sb2 shows low figure of merit(z T = 0.23 at 723 K) for its poor electrical conductivity.In this study,a series of Mg(3-x)LixSb2 bulk materials have been prepared by high-energy ball milling and spark plasma sintering(SPS) process.Electrical transport measurements on these materials revealed significant improvement on the power factor with respect to the undoped sample,which can be essentially attributed to the increased carrier concentration,leading to a maximum z T of0.59 at 723 K with the optimum doping level x = 0.01.Additionally,the engineering z T and energy conversion efficiency are calculated to be 0.235 and 4.89%,respectively.To our best knowledge,those are the highest values of all reported p-type Mg3Sb2-based compounds with single element doping.展开更多
Nitrogen-doped, p-type ZnO thin films were grown successfully on sapphire (0001) substrates by using atomic layer epitaxy (ALE). Zn(C2H5)2 [Diethylzinc, DEZn], H2O and NH3 were used as a zinc precursor, an oxidant and...Nitrogen-doped, p-type ZnO thin films were grown successfully on sapphire (0001) substrates by using atomic layer epitaxy (ALE). Zn(C2H5)2 [Diethylzinc, DEZn], H2O and NH3 were used as a zinc precursor, an oxidant and a doping source gas, respectively. The lowest electrical resistivity of the p-type ZnO films grown by ALE and annealed at 1000 ℃ in an oxygen atmosphere for 1 h was 18.3 Ω·cm with a hole concentration of 3.71×1017 cm-3. Low temperature-photoluminescence analysis and time-dependent Hall measurement results support that the nitrogen-doped ZnO after annealing is a p-type semiconductor.展开更多
Highly conductive boron-doped hydrogenated mieroerystalline silicon (μc-Si:H) films are prepared by very high frequency plasma enhanced chemical vapour deposition (VHF PECVD) at the substrate temperatures (Ts)...Highly conductive boron-doped hydrogenated mieroerystalline silicon (μc-Si:H) films are prepared by very high frequency plasma enhanced chemical vapour deposition (VHF PECVD) at the substrate temperatures (Ts) ranging from 90℃ to 270℃. The effects of Ts on the growth and properties of the films are investigated. Results indicate that the growth rate, the electrical (dark conductivity, carrier concentration and Hall mobility) and structural (crystallinity and grain size) properties are all strongly dependent on Ts. As Ts increases, it is observed that 1) the growth rate initially increases and then arrives at a maximum value of 13.3 nm/min at Ts=210℃, 2) the crystalline volume fraction (Xc) and the grain size increase initially, then reach their maximum values at TS=140℃, and finally decrease, 3) the dark conductivity (σd), carrier concentration and Hall mobility have a similar dependence on Ts and arrive at their maximum values at Ts-190℃. In addition, it is also observed that at a lower substrate temperature Ts, a higher dopant concentration is required in order to obtain a maximum σd.展开更多
A mathematical model linking thermoelasticity to photothermal experiments is proposed with the consideration of the photothermal effect.The system equations for coupled plasma,heat conduction with phase-lags(PLs),and ...A mathematical model linking thermoelasticity to photothermal experiments is proposed with the consideration of the photothermal effect.The system equations for coupled plasma,heat conduction with phase-lags(PLs),and motion equations are introduced and solved by using the Laplace transform technique.The photothermal,thermal,and elastic waves in a rotating solid cylinder of semiconductor material are analyzed with the proposed model.The cylinder surface is constrained and subjected to a time-dependent pulse heat flux.The sensitivity of the physical fields for the angular velocity,PLs,and thermal vibration parameters is investigated.In addition,the effects of the effective parameters on the physical quantities are graphically illustrated and discussed in detail.展开更多
Experimentally the plateaus characteristic for the integer quantum Hall effect is obtained in vicinity of specific values of the magnetic induction. The paper demonstrates that the ratios of these induction values to ...Experimentally the plateaus characteristic for the integer quantum Hall effect is obtained in vicinity of specific values of the magnetic induction. The paper demonstrates that the ratios of these induction values to carrier concentration in the planar crystalline samples approach systematically the quanta of the magnetic flux important for the behavior of superconductors. Moreover, the same quanta can be deduced from the Landau levels theory and their application in the magnetoresistance theory gives results being in accordance with experiments. The quanta of the magnetic flux similar to those for the integer quantum Hall effect can be obtained also for the fractional quantum Hall effect. This holds on condition the experimental ratio of the magnetic flux to carrier concentration is multiplied by the filling factor of the Landau level.展开更多
The carrier screening effect occurs commonly in dielectric materials. It reduces the electric potential gradient, thus negatively affecting the functionality of resistive random access memory (RRAM) devices. An Au/Z...The carrier screening effect occurs commonly in dielectric materials. It reduces the electric potential gradient, thus negatively affecting the functionality of resistive random access memory (RRAM) devices. An Au/ZnO film/Al-doped ZnO device fabricated in this work exhibited no resistive switching (RS), which was attributed to the carrier screening effect. Therefore, annealing was used for alleviating the screening effect, significantly enhancing the RS property. In addition, different on/off ratios were obtained for various bias values, and the screening effect was accounted for by investigating electron transport mechanisms. Furthermore, different annealing temperatures were employed to modulate the free carrier concentration in ZnO films to alleviate the screening effect. The maximal on/off ratio reached 10s at an annealing temperature of 600 ℃, yielding the lowest number of free carriers and the weakest screening effect in ZnO films. This work investigates the screening effect in RS devices. The screening effect not only modulates the characteristics of memory devices but also provides insight into the mechanism of RS in these devices.展开更多
Semiconductor InSe with wide bandgap and layered crystal structure is expected to be a promising thermoelectric material,and its excellent plasticity brings great potential applications in flexible and wearable thermo...Semiconductor InSe with wide bandgap and layered crystal structure is expected to be a promising thermoelectric material,and its excellent plasticity brings great potential applications in flexible and wearable thermoelectric devices.To advance its thermoelectric performance,this work systematically investigates the carrier and phonon transport properties in n-type InSe.It is found that InSe compound presents an exceptional dynamic carrier transport property due to the amphoteric indium(In+and In^(3+)),which contributes to favorable temperature-dependent increasing carrier concentration.More importantly,with S alloying in InSe,the carrier concentration can be further enhanced from∼3.2×10^(13) cm–3 in InSe to∼4.8×10^(15) cm^(-3) in InSe_(0.97)S_(0.03) at 300 K,because S(χP∼2.58)with larger Pauling electronegativity than Se(χP∼2.55)can induce more In3+state to increase carrier concentration in matrix.This boosted dynamic carrier transport property benefits an obviously enhanced power factor.Additionally,InSe compound presents intrinsically low thermal conductivity∼1.6 W m^(-1) K^(-1) at 300 K due to low-symmetry crystal structure and strong anharmonicity.This work indicates that the special dynamic carrier transport property and intrinsically low thermal conductivity in InSe make it as a worthexpecting thermoelectric material.展开更多
GeTe-based materials have attracted significant attention as high-efficiency thermoelectric materials for mid-temperature applications.However,GeTe thin-film materials with thermoelectric performances comparable to th...GeTe-based materials have attracted significant attention as high-efficiency thermoelectric materials for mid-temperature applications.However,GeTe thin-film materials with thermoelectric performances comparable to that of their bulk counterparts have not yet been reported,because of their unsatisfactory electrical and thermal properties caused by their poor crystal quality and high carrier concentration.Herein,a series of Sb-doped GeTe films and devices with remarkable thermoelectric performances are presented.These films are prepared through magnetron sputtering deposition at 553 K and exhibit a unique microstructure that consists of coarse-and fine-sized grains with high crystallization quality.The fine grains enhance the scattering associated with phonon transport and the coarse grains provide electron transport channels,which can suppress the thermal conductivity without obviously sacrificing the electrical conductivity.Moreover,Sb doping can effectively optimize the carrier concentration and increase the carrier effective mass,while introducing point defects and stacking faults to further scatter the phonon transport and decrease the thermal conductivity.Consequently,a peak power factor of 22.37μW cm−1 K−2 is obtained at 703 K and a maximum thermoelectric figure of merit of 1.53 is achieved at 673 K,which are substantially larger than the values reported in the existing literature.A flexible thermoelectric generator is designed and fabricated using Sb-doped GeTe films deposited on polyimide and achieves a maximum output power density of 2.22×103 W m−2 for a temperature difference of 300 K.展开更多
Heavy rare-earth element doping can effectively strengthen phonon scattering,suppress the lattice thermal conductivity,and enhance the overall thermoelectric performance of GeTe.However,the large electronegativity dif...Heavy rare-earth element doping can effectively strengthen phonon scattering,suppress the lattice thermal conductivity,and enhance the overall thermoelectric performance of GeTe.However,the large electronegativity difference between rare-earth elements(such as La,Eu,and Gd)and Ge refrains the doping limit of rare-earth elements below 1 mol.%in GeTe.Here,compared with other rare earth elements,Lu was found to have a relatively small radius and electronegativity difference with Ge,which can induce a high doping level in GeTe.The result shows that Lu doping effectively reduces the lattice thermal conductivity from 0.77 W^(−1) m K^(−1) of GeTe to 0.35 W m^(−1) K^(−1) of Ge_(0.98)Lu_(0.02)Te at 673 K,and further induces a high zT value of 1.5 in Ge_(0.98)Lu_(0.02)Te at 673 K.Extra Sb alloying optimizes the carrier concentration from 1.02×10^(21) cm^(−3) of Ge_(0.98)Lu_(0.02)Te to 1.77×10^(20) cm^(−3) of Ge0.90Lu0.02Sb0.08Te,which results in a reasonable power factor of 33.82μW cm^(−1) K^(−2) and a low electrical thermal conductivity of 0.75 W m^(−1) K^(−1) at 673 K in Ge_(0.90)Lu_(0.02)Sb_(0.08)Te.Correspondingly,a peak zT of 1.75 at 673 K and an average zT of 0.92 within the temperature range of 303–723 K are obtained in Ge_(0.9)Lu_(0.02)Sb_(0.08)Te.This study indicates that Lu and Sb co-doping can effectively boost the thermoelectric performance of GeTe-based thermoelectric materials.展开更多
Due to the complex crystal structure for low lattice thermal conductivity and the tunable valence bands for superior electronic performance,CaAl_(2)Si_(2)-structured AB_(2)C_(2) Zintl compounds have been frequently pr...Due to the complex crystal structure for low lattice thermal conductivity and the tunable valence bands for superior electronic performance,CaAl_(2)Si_(2)-structured AB_(2)C_(2) Zintl compounds have been frequently proven as promising p-type thermoelectric materials.In this work,thermoelectric properties of CaMg_(2)Bi_(2) are systematically investigated in a broad carrier concentration(10^(18)-10^(20) cm^(-3))through Agdoping for comprehensively evaluating its potential for thermoelectric applications.The broad carrier concentration enables a well assessment of the carrier transport properties by single parabolic band with acoustic phonon scattering and a revelation of the carrier transport by multiple valence orbitals when the carrier concentration higher than ~2×10^(19) cm^(-3),leading to a significant enhancement in electronic performance.With the help of additional point defect phonon scattering introduced by BaMg_(2)Bi_(2)-alloying,a reduction in lattice thermal conductivity in the entire temperature range and the lowest one of ~0.7 W/m-K are achieved,leading to a 100% enhancement in average zTave.in addition to the contribution of a multiband transport.This work not only demonstrates CaMg_(2)Bi_(2) as a promising thermoelectric material,but also provides a well understanding of its underlying material physics.展开更多
基金Project supported by the National Key R&D Program of China (Grant No. 2021YFA1202802)the National Natural Science Foundation of China (Grant Nos. 21875280,21991150, 21991153, and 22022205)+1 种基金the CAS Project for Young Scientists in Basic Research (Grant No. YSBR-054)the Special Foundation for Carbon Peak Neutralization Technology Innovation Program of Jiangsu Province,China(Grant No. BE2022026)
文摘The charge carrier concentration profile is a critical factor that determines semiconducting material properties and device performance.Dielectric force microscopy(DFM)has been previously developed to map charge carrier concentrations with nanometer-scale spatial resolution.However,it is challenging to quantitatively obtain the charge carrier concentration,since the dielectric force is also affected by the mobility.Here,we quantitative measured the charge carrier concentration at the saturation mobility regime via the rectification effect-dependent gating ratio of DFM.By measuring a series of n-type GaAs and GaN thin films with mobility in the saturation regime,we confirmed the decreased DFM-measured gating ratio with increasing electron concentration.Combined with numerical simulation to calibrate the tip–sample geometry-induced systematic error,the quantitative correlation between the DFM-measured gating ratio and the electron concentration has been established,where the extracted electron concentration presents high accuracy in the range of 4×10^(16)–1×10^(18)cm^(-3).We expect the quantitative DFM to find broad applications in characterizing the charge carrier transport properties of various semiconducting materials and devices.
基金Funded by the National Natural Science Foundation of China(Nos.51278058,41404095,51277012,61201233)the Fundamental Research Funds for the Central Universities(Nos.2013G1241120,2013G1241107,2013G1241114,CHD2011ZD004)+1 种基金Research Fund of Shaanxi Provincial Research Center for Telecommunication ASIC Design(No.SXASIC2014-1)the Shaanxi Science and Technology Research and Development Program(No.2013KJXX-93)
文摘Intrinsic carrier concentration(ni) is one of the most important physical parameters for understanding the physics of strained Si and Si1-xGex materials as well as for evaluating the electrical properties of Si-based strained devices. Up to now, the report on quantitative results of intrinsic carrier concentration in strained Si and Si1-xGex materials has been still lacking. In this paper, by analyzing the band structure of strained Si and Si1-xGex materials, both the effective densities of the state near the top of valence band and the bottom of conduction band( Nc and Nv) at 218, 330 and 393 K and the intrinsic carrier concentration related to Ge fraction(x) at 300 K were systematically studied within the framework of KP theory and semiconductor physics. It is found that the intrinsic carrier concentration in strained Si(001) and Si1-xGex(001) and(101) materials at 300 K increases significantly with increasing Ge fraction(x), which provides valuable references to understand the Sibased strained device physics and design.
基金This work was supported by the National Basic Research Program of China (No. 2013CB932602), the Program of Introducing Talents of Discipline to Universities (No. B14003), National Natural Science Foundation of China (Nos. 51527802, 51372023 and 51232001), Beijing Municipal Science & Technology Commission, the Fundamental Research Funds for Central Universities.
文摘Sandwich-style memristor devices were synthesized by electrochemical deposition with a ZnO film serving as the active layer between Al-doped ZnO (AZO) and Au electrodes. The carrier concentration of the ZnO films is controlled by adding HNO3 during the growth process. A resulting increase in carrier concentration from 10^17 to 10^19 cm^-3 was observed, along with a corresponding drop in the on--off ratio from 6,437% to 100%. The resistive switching characteristics completely disappeared when the carrier concentration was above 1029 cm-3, making it unsuitable for a memory device. The decreasing switching ratio is attributed to a reduction in the driving force for oxygen vacancy drift. Systematic analysis of the migration of oxygen vacancies is presented, including the concentration gradient and electrical potential gradient. Such oxygen vacancy migration dynamics provide insight into the mechanisms of the oxygen vacancy drift and provide valuable information for industrial production of memristor devices.
基金supported financially by the National Natural Science Foundation of China(Nos.51772012 and 51671015)the National Key Research and Development Program of China(Nos.2018YFB0703600 and 2018YFA0702100)+5 种基金the Beijing Natural Science Foundation(No.JQ18004)the Shenzhen Peacock Plan Team(No.KQTD2016022619565991)111 Project(No.B17002)financial support from Postdoctoral Science Foundation of China(No.2019M660399)the National Postdoctoral Program for Innovative Talents(No.BX20190028)support from the National Science Fund for Distinguished Young Scholars(No.51925101)。
文摘Possessing inherently low thermal conductivity,BiSbSe_(3) is a promising thermoelectric material for medium temperature.Therefore,to substantially optimize the thermoelectric performance of BiSbSe_(3),researchers mainly focus on the strategies to improve its electrical transport properties.Among these strongly coupled thermoelectric parameters,carrier concentration and effective mass are two intrinsic variables to decisively affect the electrical transport properties.In this work,Cl as a donor dopant is effective to provide extra electrons in n-type BiSbSe_(3),and the carrier concentration and effective mass can be well optimized simultaneously with increasing Cl content owing to the multiple conduction bands in BiSbSe_(3).What’s more,maximum weighted mobility~53 cm^(2)V^(-1)s^(-1)is obtained in Cl-doped BiSbSe_(3),which contributes to a largely enhanced power factor~4.8μW cm^(-1)K^(-2)at room temperature and outperforms other halogen-doped BiSbSe_(3) samples.Finally,combining the significantly enhanced power factor and maintained low thermal conductivity,a maximum ZT~1.0 is achieved in Cl-doped BiSbSe_(3) at 800 K.
基金supported by the MSIT(Ministry of Science and ICT),Korea,under the ITRC(Information Technology Research Center)support program supervised by the IITP(Institute of Information&Communications Technology Planning&Evaluation)(ⅡTP-2020-2020-0-01655)funded and conducted under the Competency Development Program for Industry Specialists of the Korean Ministry of Trade,Industry and Energy(MOTIE),operated by Korea Institute for Advancement of Technology(KIAT)(No.P0012453,Next-generation Display Expert Training Project for Innovation Process and Equipment,Materials Engineers)。
文摘This study proposed a strategy for effectively diminishing the carrier concentration in Cu_(2)Te by introducing graphene sheets,Based on thermoelectric property measurements and single parabolic band modeling,the incorporated graphene effectively reduced the carrier concentration,not only enhancing the thermoelectric performance of the Cu_(2)Te/graphene composite but also substantially improving its figure of merit up to ~1.47 at 1000 K,which is 268% higher than that of pristine Cu_(2)Te,This study gives an insight into the control of carrier concentration and thermoelectric properties in Cu_(2)Te,and it could be extended to other copper chalcogenides for excellent thermoelectrics.
基金supported by the National Natural Science Foundation of China(No.U19A2018)the China National University Student Innovation and Entrepreneurship Training Program(S202310530059)。
文摘All-solid-state fluoride ion batteries(FIBs)have been recently considered as a post-lithium-ion battery system due to their high safety and high energy density.Just like all solid-state lithium batteries,the key to the development of FIBs lies in room-temperature electrolytes with high ionic conductivity.β-KSbF_(4) is a kind of promising solid-state electrolyte for FIBs owing to its rational ionic conductivity and relatively wide electrochemical stability window at room temperature.However,the previous synthesis routes ofβ-KSbF_(4) required the use of highly toxic hydrofluoric acid and the ionic conductivity of as-prepared product needs to be further improved.Herein,the β-KSbF_(4) sample with an ionic conductivity of 1.04×10^(-4)s cm^(-1)(30°C)is synthesized through the simple solid-state route.In order to account for the high ionic conductivity of the as-synthesizedβ-KSbF_(4),X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive X-ray spectroscopy(EDS)are used to characterize the physic-ochemical properties.The results show that the as-synthesizedβ-KSbF_(4) exhibits higher carrier concentra-tion of 1.0×10^(-6)S cm-Hz^(-1)K and hopping frequency of 1.31×10^(6)Hz at 30°C due to the formation of the fluorine vacancies.Meanwhile,the hopping frequency shows the same trend as the changes of ionic conductivity with the changes of temperature,while the carrier concentration is found to be almost con-stant.The two different trends indicate the hopping frequency is mainly responsible for the ionic conduc-tion behavior withinβ-KSbF_(4).Furthermore,the all-solid-state FIBs,in which Ag and Pb+PbF_(2) are adopted as cathode and anode,andβ-KSbF_(4) as fluoride ion conductor,are capable of reversible charge and discharge.The assembled FIBs show a discharge capacity of 108.4 mA h g^(-1) at 1st cycle and 74.2 mA h g^(-1) at 50th cycle.Based on an examination of the capacity decay mechanism,it has been found that deterioration of the electrolyte/electrode interface is an important reason for hindering the commer-cial application of FIBs.Hence,the in-depth comprehension of the ion transport characteristics inβ-KSbF_(4) and the interpretation of the capacity fading mechanism will be conducive to promoting development of high-performanceFIBs.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2018YFA0702100and 2022YFB3803900)the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences (CAS)’ Large-Scale Scientific Facility (Grant No. U1932106)the Sichuan University Innovation Research Program of China (Grant No. 2020SCUNL112)。
文摘AgCrSe2-based compounds have attracted much attention as an environmentally friendly thermoelectric material in recent years due to the intriguing liquid-like properties.However,the ultra-low carrier concentration and the high Ag_(Cr)deep-level defects limit the overall thermoelectric performance.Here,we successfully introduced Pb into Ag-deficient Ag_(0.97)CrSe_(2) alloys to tune the carrier concentration across a broad temperature range.The Pb^(2+) as an acceptor dopant preferentially occupies Cr sites,boosting the hole carrier concentration to 1.77×10^(19) cm^(-3) at room temperature.Furthermore,the Pb strongly inhibits the creation of intrinsic Ag_(Cr) defects,weakens the increased thermal excited ionization with the increasing temperature and slowed the rising trend of the carrier concentration.The designed carrier concentration matches the theoretically predicted optimized one over the entire temperature range,leading to a remarkable enhancement in power factor,especially the maximum power factor of ~500 μW·m^(-1)·K^(-2) at 750 K is superior to most previous results.Additionally,the abundant point defects promote phonon scattering,thus reducing the lattice thermal conductivity.As a result,the maximum figure of merit zT(~0.51 at 750 K) is achieved in Ag_(0.97)Cr_(0.995)Pb_(0.005)Se_(2).This work confirms the feasibility of manipulating deep-level defects to achieve temperature-dependent optimal carrier concentration and provides a valuable guidance for other thermoelectric materials.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52071041, 11874356, 51802034)supported by the Key Research Program of Frontier Sciences, CAS (Grant No.QYZDB-SSW-SLH016)
文摘Mg_(3)Sb_(2)has attracted intensive attention as a typical Zintl-type thermoelectric material.Despite the exceptional thermoelectric performance in n-type Mg_(3)Sb_(2),the dimensionless figure of merit(zT)of p-type Mg_(3)Sb_(2)remains lower than 1,which is mainly attributed to its inferior electrical properties.Herein,we synergistically optimize the thermoelectric properties of p-type Mg_(3)Sb_(2)materials via codoping of Cd and Ag,which were synthesized by high-energy ball milling combined with hot pressing.It is found that Cd doping not only increases the carrier mobility of p-type Mg_(3)Sb_(2),but also diminishes its thermal conductivity(κ_(tot)),with Mg_(2.85)Cd_(0.5)Sb_(2)achieving a lowκtot value of∼0.67 W m^(−1)K^(−1)at room temperature.Further Ag doping elevates the carrier concentration,so that the power factor is optimized over the entire temperature range.Eventually,a peak zT of∼0.75 at 773 K and an excellent average zT of∼0.41 over 300−773 K are obtained in Mg_(2.82)Ag_(0.03)Cd_(0.5)Sb_(2),which are∼240%and∼490%higher than those of pristine Mg_(3.4)Sb_(2),respectively.This study provides an effective pathway to synergistically improve the thermoelectric performance of p-type Mg_(3)Sb_(2)by codoping Cd and Ag,which is beneficial to the future applications of Mg_(3)Sb_(2)-based thermoelectric materials.
基金supported by the National Natural Science Foundation of China(Grant nos.21773218,61974063)the Sichuan Province(Grant no.2018JY0206)the China Academy of Engineering Physics(Grant no.YZJJLX2018007)。
文摘Sensitive and reliable X-ray detectors are essential for medical radiography,industrial inspection and security screening.Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence.Three-dimensional(3 D)organic-inorganic hybrid lead halide perovskites are promising for direct X-ray detection-they show improved sensitivity compared to conventional X-ray detectors.However,their high and unstable dark current,caused by ion migration and high dark carrier concentration in the 3 D hybrid perovskites,limits their performance and long-term operation stability.Here we report ultrasensitive,stable X-ray detectors made using zero-dimensional(0 D)methylammonium bismuth iodide perovskite(MA3Bi2I9)single crystals.The 0 D crystal structure leads to a high activation energy(Ea)for ion migration(0.46 e V)and is also accompanied by a low dark carrier concentration(~10^6 cm^-3).The X-ray detectors exhibit sensitivity of 10,620μC Gy-1 air cm-2,a limit of detection(Lo D)of 0.62 nG yairs-1,and stable operation even under high applied biases;no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of^23,800 m Gyair,equivalent to>200,000 times the dose required for a single commercial X-ray chest radiograph.Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1601213 and 51572287)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH013)
文摘The Zintl compound Mg3Sb2 has been recently identified as promising thermoelectric material owing to its high thermoelectric performance and cost-effective,nontoxicity and environment friendly characteristics.However,the intrinsically p-type Mg3Sb2 shows low figure of merit(z T = 0.23 at 723 K) for its poor electrical conductivity.In this study,a series of Mg(3-x)LixSb2 bulk materials have been prepared by high-energy ball milling and spark plasma sintering(SPS) process.Electrical transport measurements on these materials revealed significant improvement on the power factor with respect to the undoped sample,which can be essentially attributed to the increased carrier concentration,leading to a maximum z T of0.59 at 723 K with the optimum doping level x = 0.01.Additionally,the engineering z T and energy conversion efficiency are calculated to be 0.235 and 4.89%,respectively.To our best knowledge,those are the highest values of all reported p-type Mg3Sb2-based compounds with single element doping.
文摘Nitrogen-doped, p-type ZnO thin films were grown successfully on sapphire (0001) substrates by using atomic layer epitaxy (ALE). Zn(C2H5)2 [Diethylzinc, DEZn], H2O and NH3 were used as a zinc precursor, an oxidant and a doping source gas, respectively. The lowest electrical resistivity of the p-type ZnO films grown by ALE and annealed at 1000 ℃ in an oxygen atmosphere for 1 h was 18.3 Ω·cm with a hole concentration of 3.71×1017 cm-3. Low temperature-photoluminescence analysis and time-dependent Hall measurement results support that the nitrogen-doped ZnO after annealing is a p-type semiconductor.
文摘Highly conductive boron-doped hydrogenated mieroerystalline silicon (μc-Si:H) films are prepared by very high frequency plasma enhanced chemical vapour deposition (VHF PECVD) at the substrate temperatures (Ts) ranging from 90℃ to 270℃. The effects of Ts on the growth and properties of the films are investigated. Results indicate that the growth rate, the electrical (dark conductivity, carrier concentration and Hall mobility) and structural (crystallinity and grain size) properties are all strongly dependent on Ts. As Ts increases, it is observed that 1) the growth rate initially increases and then arrives at a maximum value of 13.3 nm/min at Ts=210℃, 2) the crystalline volume fraction (Xc) and the grain size increase initially, then reach their maximum values at TS=140℃, and finally decrease, 3) the dark conductivity (σd), carrier concentration and Hall mobility have a similar dependence on Ts and arrive at their maximum values at Ts-190℃. In addition, it is also observed that at a lower substrate temperature Ts, a higher dopant concentration is required in order to obtain a maximum σd.
文摘A mathematical model linking thermoelasticity to photothermal experiments is proposed with the consideration of the photothermal effect.The system equations for coupled plasma,heat conduction with phase-lags(PLs),and motion equations are introduced and solved by using the Laplace transform technique.The photothermal,thermal,and elastic waves in a rotating solid cylinder of semiconductor material are analyzed with the proposed model.The cylinder surface is constrained and subjected to a time-dependent pulse heat flux.The sensitivity of the physical fields for the angular velocity,PLs,and thermal vibration parameters is investigated.In addition,the effects of the effective parameters on the physical quantities are graphically illustrated and discussed in detail.
文摘Experimentally the plateaus characteristic for the integer quantum Hall effect is obtained in vicinity of specific values of the magnetic induction. The paper demonstrates that the ratios of these induction values to carrier concentration in the planar crystalline samples approach systematically the quanta of the magnetic flux important for the behavior of superconductors. Moreover, the same quanta can be deduced from the Landau levels theory and their application in the magnetoresistance theory gives results being in accordance with experiments. The quanta of the magnetic flux similar to those for the integer quantum Hall effect can be obtained also for the fractional quantum Hall effect. This holds on condition the experimental ratio of the magnetic flux to carrier concentration is multiplied by the filling factor of the Landau level.
基金Acknowledgements This work was supported by the National Basic Research Program of China (No. 2013CB932602), the Program of Introducing Talents of Discipline to Universities (No. B14003), National Natural Science Foundation of China (Nos. 51527802, 51372023, and 51232001), Beijing Municipal Science & Technology Commission, the Fundamental Research Funds for Central Universities.
文摘The carrier screening effect occurs commonly in dielectric materials. It reduces the electric potential gradient, thus negatively affecting the functionality of resistive random access memory (RRAM) devices. An Au/ZnO film/Al-doped ZnO device fabricated in this work exhibited no resistive switching (RS), which was attributed to the carrier screening effect. Therefore, annealing was used for alleviating the screening effect, significantly enhancing the RS property. In addition, different on/off ratios were obtained for various bias values, and the screening effect was accounted for by investigating electron transport mechanisms. Furthermore, different annealing temperatures were employed to modulate the free carrier concentration in ZnO films to alleviate the screening effect. The maximal on/off ratio reached 10s at an annealing temperature of 600 ℃, yielding the lowest number of free carriers and the weakest screening effect in ZnO films. This work investigates the screening effect in RS devices. The screening effect not only modulates the characteristics of memory devices but also provides insight into the mechanism of RS in these devices.
基金National Key Research and Development Program of China,Grant/Award Numbers:2018YFA0702100,2018YFB0703600National Natural Science Foundation of China,Grant/Award Numbers:51772012,51671015+4 种基金Beijing Natural Science Foundation,Grant/Award Number:JQ18004Shenzhen Peacock Plan team,Grant/Award Numbers:KQTD2016022619565991,111Project:B17002National Postdoctoral Program for Innovative Talents,Grant/Award Numbers:BX20190028,BX20200028Postdoctoral Science Foundation of China,Grant/Award Number:2019M660399National Science Fund for Distinguished Young Scholars,Grant/Award Number:51925101。
文摘Semiconductor InSe with wide bandgap and layered crystal structure is expected to be a promising thermoelectric material,and its excellent plasticity brings great potential applications in flexible and wearable thermoelectric devices.To advance its thermoelectric performance,this work systematically investigates the carrier and phonon transport properties in n-type InSe.It is found that InSe compound presents an exceptional dynamic carrier transport property due to the amphoteric indium(In+and In^(3+)),which contributes to favorable temperature-dependent increasing carrier concentration.More importantly,with S alloying in InSe,the carrier concentration can be further enhanced from∼3.2×10^(13) cm–3 in InSe to∼4.8×10^(15) cm^(-3) in InSe_(0.97)S_(0.03) at 300 K,because S(χP∼2.58)with larger Pauling electronegativity than Se(χP∼2.55)can induce more In3+state to increase carrier concentration in matrix.This boosted dynamic carrier transport property benefits an obviously enhanced power factor.Additionally,InSe compound presents intrinsically low thermal conductivity∼1.6 W m^(-1) K^(-1) at 300 K due to low-symmetry crystal structure and strong anharmonicity.This work indicates that the special dynamic carrier transport property and intrinsically low thermal conductivity in InSe make it as a worthexpecting thermoelectric material.
基金supported by the National Natural Science Foundation of China(51972094 and 52002107)Hebei Provincial Department of Science and Technology(236Z4403G)+1 种基金Research Innovation Team Project of Hebei University(IT2023A04,150000321008)supported in part by the Micro-analysis Center and the High-Performance Computing Center of Hebei University。
基金financial support from the Ministry of Science and Technology of China(Nos.2017YFA0700702,2017YFA0700705)the National Natural Science Foundation of China(Nos.52073290,51927803)+2 种基金the Liaoning Province Science and Technology Plan Project(2022-MS-011)the Science Fund for Distinguished Young Scholars of Liaoning Province(2023JH6/100500004)the Science and Technology Plan Projects of Shenyang(No.21108901).
文摘GeTe-based materials have attracted significant attention as high-efficiency thermoelectric materials for mid-temperature applications.However,GeTe thin-film materials with thermoelectric performances comparable to that of their bulk counterparts have not yet been reported,because of their unsatisfactory electrical and thermal properties caused by their poor crystal quality and high carrier concentration.Herein,a series of Sb-doped GeTe films and devices with remarkable thermoelectric performances are presented.These films are prepared through magnetron sputtering deposition at 553 K and exhibit a unique microstructure that consists of coarse-and fine-sized grains with high crystallization quality.The fine grains enhance the scattering associated with phonon transport and the coarse grains provide electron transport channels,which can suppress the thermal conductivity without obviously sacrificing the electrical conductivity.Moreover,Sb doping can effectively optimize the carrier concentration and increase the carrier effective mass,while introducing point defects and stacking faults to further scatter the phonon transport and decrease the thermal conductivity.Consequently,a peak power factor of 22.37μW cm−1 K−2 is obtained at 703 K and a maximum thermoelectric figure of merit of 1.53 is achieved at 673 K,which are substantially larger than the values reported in the existing literature.A flexible thermoelectric generator is designed and fabricated using Sb-doped GeTe films deposited on polyimide and achieves a maximum output power density of 2.22×103 W m−2 for a temperature difference of 300 K.
基金supported by the Australian Research Council,the Innovation centre for Sustainable Steel project,and the QUT capacity building professor program.K.Guo thanks the support of the National Key Research and Development Program of China(No.2018YFA0702100)。
文摘Heavy rare-earth element doping can effectively strengthen phonon scattering,suppress the lattice thermal conductivity,and enhance the overall thermoelectric performance of GeTe.However,the large electronegativity difference between rare-earth elements(such as La,Eu,and Gd)and Ge refrains the doping limit of rare-earth elements below 1 mol.%in GeTe.Here,compared with other rare earth elements,Lu was found to have a relatively small radius and electronegativity difference with Ge,which can induce a high doping level in GeTe.The result shows that Lu doping effectively reduces the lattice thermal conductivity from 0.77 W^(−1) m K^(−1) of GeTe to 0.35 W m^(−1) K^(−1) of Ge_(0.98)Lu_(0.02)Te at 673 K,and further induces a high zT value of 1.5 in Ge_(0.98)Lu_(0.02)Te at 673 K.Extra Sb alloying optimizes the carrier concentration from 1.02×10^(21) cm^(−3) of Ge_(0.98)Lu_(0.02)Te to 1.77×10^(20) cm^(−3) of Ge0.90Lu0.02Sb0.08Te,which results in a reasonable power factor of 33.82μW cm^(−1) K^(−2) and a low electrical thermal conductivity of 0.75 W m^(−1) K^(−1) at 673 K in Ge_(0.90)Lu_(0.02)Sb_(0.08)Te.Correspondingly,a peak zT of 1.75 at 673 K and an average zT of 0.92 within the temperature range of 303–723 K are obtained in Ge_(0.9)Lu_(0.02)Sb_(0.08)Te.This study indicates that Lu and Sb co-doping can effectively boost the thermoelectric performance of GeTe-based thermoelectric materials.
基金supported by Shanghai Natural Science Foundation(19ZR1459900)the Fundamental Research Funds for the Central Universities.
文摘Due to the complex crystal structure for low lattice thermal conductivity and the tunable valence bands for superior electronic performance,CaAl_(2)Si_(2)-structured AB_(2)C_(2) Zintl compounds have been frequently proven as promising p-type thermoelectric materials.In this work,thermoelectric properties of CaMg_(2)Bi_(2) are systematically investigated in a broad carrier concentration(10^(18)-10^(20) cm^(-3))through Agdoping for comprehensively evaluating its potential for thermoelectric applications.The broad carrier concentration enables a well assessment of the carrier transport properties by single parabolic band with acoustic phonon scattering and a revelation of the carrier transport by multiple valence orbitals when the carrier concentration higher than ~2×10^(19) cm^(-3),leading to a significant enhancement in electronic performance.With the help of additional point defect phonon scattering introduced by BaMg_(2)Bi_(2)-alloying,a reduction in lattice thermal conductivity in the entire temperature range and the lowest one of ~0.7 W/m-K are achieved,leading to a 100% enhancement in average zTave.in addition to the contribution of a multiband transport.This work not only demonstrates CaMg_(2)Bi_(2) as a promising thermoelectric material,but also provides a well understanding of its underlying material physics.