ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, t...ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, the deep-level transient spectroscopy （DLTS） and the photoluminescence （PL） spectra of the samples were measured. DLTS shows two deep-level centres of E1 （Ec-0.13±0.02eV） and E2 （Ec-0.43±0.05eV） in sample 1202a, which has a ZnO/p-Si heterostructure. A deep level at Ec-0.13±0.01 eV was also obtained from the I -T characteristics. It was considered to be the same as E1 obtained from DLTS measurement. The emission related to this deep level center was detected by PL spectra. In addition, the energy location and the relative trap density of E1 was varied when the total gas flow rate was changed.展开更多
The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties ...The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties were investigated.A distinct bipolar resistive switching behavior of the devices was observed at room temperature.The resistance ratio R_（HRS）/RLRS of high resistance state and low resistance state is as large as four orders of magnitude with a readout voltage of 2.0 V.The dominant conduction mechanism of the device is trap-controlled space charge limited current（SCLC）.The devices exhibit good durability under 1×10^3cycles and the degradation is invisible for more than 10^6 s.展开更多
ZnCo2O4/Si heterostructures have been fabricated by a pulsed laser deposition method, and their transport behaviors and photovoltaic properties have been characterized. The ZnCo2O4/Si heterostructures show a good rect...ZnCo2O4/Si heterostructures have been fabricated by a pulsed laser deposition method, and their transport behaviors and photovoltaic properties have been characterized. The ZnCo2O4/Si heterostructures show a good rectifying behavior at five different temperatures ranging from 50 K to 290 K. The measurements of the photovoltaic response reveals that a photovoltage of 33 mV is generated when the heterostructures are illuminated by a 532 nm laser of 250 mW/cm^2 and mechanically chopped at 2500 Hz. Both the photocurrent and the photovoltage clearly increase with the increase of the laser intensity at room temperature. However, the heterostructures＇ photovoltage peak decreases with the increase of the temperature. This work may open new perspectives for ZnCo2O4/Si heterostructure-based devices.展开更多
We report a novel structure of A1GaN/GaN heterostructure field effect transistors （HFETs） with a Si and Mg pair- doped interlayer grown on Si substrate. By optimizing the doping concentrations of the pair-doped inte...We report a novel structure of A1GaN/GaN heterostructure field effect transistors （HFETs） with a Si and Mg pair- doped interlayer grown on Si substrate. By optimizing the doping concentrations of the pair-doped interlayers, the mobility of 2DEG increases by twice for the conventional structure under 5 K due to the improved crystalline quality of the conduction channel. The proposed HFET shows a four orders lower off-state leakage current, resulting in a much higher on/off ratio （ - 10^9）. Further temperature-dependent performance of Schottky diodes revealed that the inhibition of shallow surface traps in proposed HFETs should be the main reason for the suppression of leakage current.展开更多
The n-ZnO/p-Si heterojunction was fabricated by depositing high quality single crystalline aluminium-doped n-type ZnO film on p-type Si using the laser molecular beam epitaxy technique. The heterojunction exhibited a ...The n-ZnO/p-Si heterojunction was fabricated by depositing high quality single crystalline aluminium-doped n-type ZnO film on p-type Si using the laser molecular beam epitaxy technique. The heterojunction exhibited a good rectifying behavior. The electrical properties of the heterojunction were investigated by means of temperature dependence current density-voltage measurements. The mechanism of the current transport was proposed based on the band structure of the heterojunction. When the applied bias V is lower than 0.15 V, the current follows the Ohmic behavior. When 0.15 V ~ V 〈 0.6 V, the transport property is dominated by diffusion or recombination in the junction space charge region, while at higher voltages （V 〉 0.6 V）, the space charge limited effect becomes the main transport mechanism. The current-voltage characteristic under illumination was also investigated. The photovoltage and the short circuit current density of the heterojunction aproached 270 mV and 2.10 mA/cm^2, respectively.展开更多
High mobility Si/Si_(l-x)Ge_(x)/Si p-type modulation-doped double heterostructures have been grown by RRH/VLP-CVD(rapid radiant heating/very low pressure-CVD).Hole Hall mobilities as high as about 300cm^(2)/V.s(293 K)...High mobility Si/Si_(l-x)Ge_(x)/Si p-type modulation-doped double heterostructures have been grown by RRH/VLP-CVD(rapid radiant heating/very low pressure-CVD).Hole Hall mobilities as high as about 300cm^(2)/V.s(293 K)and 7500cm^(2)/V.s(77K)have been obtained for heterostructures with x=0.3.The variation of hole mobility with temperature and the influence of Ge fraction on hole mobility were investigated.展开更多
The atomic structure and surface chemistry of GaP/Si(100)heterostructure with different pre-layers grown by molecu-lar beam epitaxy are studied.It is found that GaP epilayer with Ga-riched pre-layers on Si(100)substra...The atomic structure and surface chemistry of GaP/Si(100)heterostructure with different pre-layers grown by molecu-lar beam epitaxy are studied.It is found that GaP epilayer with Ga-riched pre-layers on Si(100)substrate has regular surface mor-phology and stoichiometric abrupt heterointerfaces from atomic force microscopes(AFMs)and spherical aberration-corrected transmission electron microscopes(ACTEMs).The interfacial dynamics of GaP/Si(100)heterostructure is investigated by X-ray photoelectron spectroscopy(XPS)equipped with an Ar gas cluster ion beam,indicating that Ga pre-layers can lower the inter-face formation energy and the bond that is formed is more stable.These results suggest that Ga-riched pre-layers are more con-ducive to the GaP nucleation as well as the epitaxial growth of GaP material on Si(100)substrate.展开更多
Si/SiC heterostructures with different growth temperatures were prepared on 6 HSiC(0001)by LPCVD.Current mode atomic force microscopy and transmission electron microscopy were employed to investigate the electrical pr...Si/SiC heterostructures with different growth temperatures were prepared on 6 HSiC(0001)by LPCVD.Current mode atomic force microscopy and transmission electron microscopy were employed to investigate the electrical properties and crystalline structure of Si/SiC heterostructures.Face-centered cubic(FCC)on hexagonal close-packing(HCP)epitaxy of the Si(111)/SiC(0001)heterostructure was realized at 900°C.As the growth temperature increases to1050°C,the<110>preferred orientation of the Si film is observed.The Si films on 6 H-SiC(0001)with different growth orientations consist of different distinctive crystalline grains:quasi-spherical grains with a general size of 20μm,and columnar grains with a typical size of 7μm×20μm.The electrical properties are greatly influenced by the grain structures.The Si film with<110>orientation on SiC(0001)consists of columnar grains,which is more suitable for the fabrication of Si/SiC devices due to its low current fluctuation and relatively uniform current distribution.展开更多
Si/SiGe/Si heterostructures grown by ultra-high-vacuum chemical vapor deposition (UHVCVD) werecharacterized by Rutherford backscattering/Channeling (RBS/C) together with high resolution X ray diffraction(HRXRD). High ...Si/SiGe/Si heterostructures grown by ultra-high-vacuum chemical vapor deposition (UHVCVD) werecharacterized by Rutherford backscattering/Channeling (RBS/C) together with high resolution X ray diffraction(HRXRD). High quality SiGe base layer was obtained. The Si/SiGe/Si heterostructures were subject to conventionalfurnace annealing and rapid thermal annealing with temperature between 750 ℃ and 910 ℃. Both strain and its re-laxation degree in SiGe layer are calculated by HRXRD combined with elastic theory, which are never reported inother literatures. The rapid thermal annealing at elevated temperature between 880 ℃ and 910 ℃ for very short timehad almost no influence on the strain in Si0.84Ge0. 16 epilayer. However, high temperature (900℃) furnace annealingfor 1h prompted the strain in Si0.84Ge0.16 layer to relax.展开更多
Mg0.2Zn0.8OMZO/La0.67Ca0.33MnOLCMO heterostructure was deposited on p-^＋-Si substrates by sol-gel spin coating technique. The Ag/MZO/LCMO/p-^＋-Si devices exhibit a bipolar, reversible, and remarkable current-voltage...Mg0.2Zn0.8OMZO/La0.67Ca0.33MnOLCMO heterostructure was deposited on p-^＋-Si substrates by sol-gel spin coating technique. The Ag/MZO/LCMO/p-^＋-Si devices exhibit a bipolar, reversible, and remarkable current-voltage characteristic at room temperature. An obvious multilevel resistive switching effect is observed in the devices. The dominant conduction mechanism of the devices is trap-controlled space charge limited current. The resistance ratio of high resistance state and low resistance state of the devices is about six orders of magnitude, and the degradation is invisible in the devices after 250 successive switching cycles. The present results suggest that the Ag/MZO/LCMO/p-^＋-Si devices may be a potential and multilevel candidate for nonvolatile memory application.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50472009, 10474091 and 50532070)
文摘ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, the deep-level transient spectroscopy （DLTS） and the photoluminescence （PL） spectra of the samples were measured. DLTS shows two deep-level centres of E1 （Ec-0.13±0.02eV） and E2 （Ec-0.43±0.05eV） in sample 1202a, which has a ZnO/p-Si heterostructure. A deep level at Ec-0.13±0.01 eV was also obtained from the I -T characteristics. It was considered to be the same as E1 obtained from DLTS measurement. The emission related to this deep level center was detected by PL spectra. In addition, the energy location and the relative trap density of E1 was varied when the total gas flow rate was changed.
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties were investigated.A distinct bipolar resistive switching behavior of the devices was observed at room temperature.The resistance ratio R_（HRS）/RLRS of high resistance state and low resistance state is as large as four orders of magnitude with a readout voltage of 2.0 V.The dominant conduction mechanism of the device is trap-controlled space charge limited current（SCLC）.The devices exhibit good durability under 1×10^3cycles and the degradation is invisible for more than 10^6 s.
基金Project supported by the National Natural Science Foundation of China(Grant No.61078057)the Natural Science Foundation of Shannxi Province,China(Grant No.2011GM6013)+1 种基金the Northwestern Polytechnical University Foundation for Fundamental Research,China(Grant Nos.JC20110270 and JC201271)the Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University,China(Grant No.LZUMMM2013001)
文摘ZnCo2O4/Si heterostructures have been fabricated by a pulsed laser deposition method, and their transport behaviors and photovoltaic properties have been characterized. The ZnCo2O4/Si heterostructures show a good rectifying behavior at five different temperatures ranging from 50 K to 290 K. The measurements of the photovoltaic response reveals that a photovoltage of 33 mV is generated when the heterostructures are illuminated by a 532 nm laser of 250 mW/cm^2 and mechanically chopped at 2500 Hz. Both the photocurrent and the photovoltage clearly increase with the increase of the laser intensity at room temperature. However, the heterostructures＇ photovoltage peak decreases with the increase of the temperature. This work may open new perspectives for ZnCo2O4/Si heterostructure-based devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.51177175 and 61274039)the National Basic Research Project of China(Grant Nos.2010CB923200 and 2011CB301903)+4 种基金the Ph.D.Program Foundation of Ministry of Education of China(Grant No.20110171110021)the International Sci.&Tech.Collaboration Program of China(Grant No.2012DFG52260)the National High-tech R&D Program of China(Grant No.2014AA032606)the Science and Technology Plan of Guangdong Province,China(Grant No.2013B010401013)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(Grant No.IOSKL2014KF17)
文摘We report a novel structure of A1GaN/GaN heterostructure field effect transistors （HFETs） with a Si and Mg pair- doped interlayer grown on Si substrate. By optimizing the doping concentrations of the pair-doped interlayers, the mobility of 2DEG increases by twice for the conventional structure under 5 K due to the improved crystalline quality of the conduction channel. The proposed HFET shows a four orders lower off-state leakage current, resulting in a much higher on/off ratio （ - 10^9）. Further temperature-dependent performance of Schottky diodes revealed that the inhibition of shallow surface traps in proposed HFETs should be the main reason for the suppression of leakage current.
基金Project supported by the Postdoctor Foundation of Hebei Province, Chinathe Natural Science Foundation of Hebei Province,China (Grant No. F2012201093)the Natural Science Foundation of Hebei University, China (Grant No. 2008127)
文摘The n-ZnO/p-Si heterojunction was fabricated by depositing high quality single crystalline aluminium-doped n-type ZnO film on p-type Si using the laser molecular beam epitaxy technique. The heterojunction exhibited a good rectifying behavior. The electrical properties of the heterojunction were investigated by means of temperature dependence current density-voltage measurements. The mechanism of the current transport was proposed based on the band structure of the heterojunction. When the applied bias V is lower than 0.15 V, the current follows the Ohmic behavior. When 0.15 V ~ V 〈 0.6 V, the transport property is dominated by diffusion or recombination in the junction space charge region, while at higher voltages （V 〉 0.6 V）, the space charge limited effect becomes the main transport mechanism. The current-voltage characteristic under illumination was also investigated. The photovoltage and the short circuit current density of the heterojunction aproached 270 mV and 2.10 mA/cm^2, respectively.
文摘High mobility Si/Si_(l-x)Ge_(x)/Si p-type modulation-doped double heterostructures have been grown by RRH/VLP-CVD(rapid radiant heating/very low pressure-CVD).Hole Hall mobilities as high as about 300cm^(2)/V.s(293 K)and 7500cm^(2)/V.s(77K)have been obtained for heterostructures with x=0.3.The variation of hole mobility with temperature and the influence of Ge fraction on hole mobility were investigated.
基金supported in part by the National Key R&D Program(Grant No.2018YFB2003305)the National Natural Science Foundation of China(Grant Nos.61774165,61704186,and 61827823)the program from SINANO(Y8AAQ11003 and Y4JAQ21005)。
文摘The atomic structure and surface chemistry of GaP/Si(100)heterostructure with different pre-layers grown by molecu-lar beam epitaxy are studied.It is found that GaP epilayer with Ga-riched pre-layers on Si(100)substrate has regular surface mor-phology and stoichiometric abrupt heterointerfaces from atomic force microscopes(AFMs)and spherical aberration-corrected transmission electron microscopes(ACTEMs).The interfacial dynamics of GaP/Si(100)heterostructure is investigated by X-ray photoelectron spectroscopy(XPS)equipped with an Ar gas cluster ion beam,indicating that Ga pre-layers can lower the inter-face formation energy and the bond that is formed is more stable.These results suggest that Ga-riched pre-layers are more con-ducive to the GaP nucleation as well as the epitaxial growth of GaP material on Si(100)substrate.
基金Supported by the National Key Research and Development Program of China(2018YFB2200500)the National Natural Science Foundation of China(51402230,51177134,21503153)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China(2017JM6075,2015JM6282)Scientific Research Program Funded by Shaanxi Provincial Education Department(17JK0335)。
文摘Si/SiC heterostructures with different growth temperatures were prepared on 6 HSiC(0001)by LPCVD.Current mode atomic force microscopy and transmission electron microscopy were employed to investigate the electrical properties and crystalline structure of Si/SiC heterostructures.Face-centered cubic(FCC)on hexagonal close-packing(HCP)epitaxy of the Si(111)/SiC(0001)heterostructure was realized at 900°C.As the growth temperature increases to1050°C,the<110>preferred orientation of the Si film is observed.The Si films on 6 H-SiC(0001)with different growth orientations consist of different distinctive crystalline grains:quasi-spherical grains with a general size of 20μm,and columnar grains with a typical size of 7μm×20μm.The electrical properties are greatly influenced by the grain structures.The Si film with<110>orientation on SiC(0001)consists of columnar grains,which is more suitable for the fabrication of Si/SiC devices due to its low current fluctuation and relatively uniform current distribution.
基金the National High Technology and Research Development Program(863 Program)of China(No.2002AA321230)partially supported by the National Natural Sciences Foundation of China(No.10075072)
文摘Si/SiGe/Si heterostructures grown by ultra-high-vacuum chemical vapor deposition (UHVCVD) werecharacterized by Rutherford backscattering/Channeling (RBS/C) together with high resolution X ray diffraction(HRXRD). High quality SiGe base layer was obtained. The Si/SiGe/Si heterostructures were subject to conventionalfurnace annealing and rapid thermal annealing with temperature between 750 ℃ and 910 ℃. Both strain and its re-laxation degree in SiGe layer are calculated by HRXRD combined with elastic theory, which are never reported inother literatures. The rapid thermal annealing at elevated temperature between 880 ℃ and 910 ℃ for very short timehad almost no influence on the strain in Si0.84Ge0. 16 epilayer. However, high temperature (900℃) furnace annealingfor 1h prompted the strain in Si0.84Ge0.16 layer to relax.
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘Mg0.2Zn0.8OMZO/La0.67Ca0.33MnOLCMO heterostructure was deposited on p-^＋-Si substrates by sol-gel spin coating technique. The Ag/MZO/LCMO/p-^＋-Si devices exhibit a bipolar, reversible, and remarkable current-voltage characteristic at room temperature. An obvious multilevel resistive switching effect is observed in the devices. The dominant conduction mechanism of the devices is trap-controlled space charge limited current. The resistance ratio of high resistance state and low resistance state of the devices is about six orders of magnitude, and the degradation is invisible in the devices after 250 successive switching cycles. The present results suggest that the Ag/MZO/LCMO/p-^＋-Si devices may be a potential and multilevel candidate for nonvolatile memory application.
