In the era of Internet of Things(Io Ts),an energy-efficient ultraviolet(UV)photodetector(PD)is highly desirable considering the massive usage scenarios such as environmental sterilization,fire alarm and corona dischar...In the era of Internet of Things(Io Ts),an energy-efficient ultraviolet(UV)photodetector(PD)is highly desirable considering the massive usage scenarios such as environmental sterilization,fire alarm and corona discharge monitoring.So far,common self-powered UV PDs are mainly based on metal-semiconductor heterostructures or p–n heterojunctions,where the limited intrinsic built-in electric field restricts further enhancement of the photoresponsivity.In this work,an extremely low-voltage field-effect UV PD is proposed using a gatedrain shorted amorphous IGZO(a-IGZO)thin film transistor(TFT)architecture.A combined investigation of the experimental measurements and technology computer-aided design(TCAD)simulations suggests that the reverse current(ⅠR)of field-effect diode(FED)is highly related with the threshold voltage(Vth)of the parental TFT,implying an enhancement-mode TFT is preferable to fabricate the field-effect UV PD with low dark current.Driven by a low bias of-0.1 V,decent UV response has been realized including large UV/visible(R_(300)/R_(550))rejection ratio(1.9×10^(3)),low dark current(1.15×10^(-12)A)as well as high photo-to-dark current ratio(PDCR,~10^(3))and responsivity(1.89 A/W).This field-effect photodiode provides a new platform to construct UV PDs with well-balanced photoresponse performance at a low bias,which is attractive for designs of large-scale smart sensor networks with high energy efficiency.展开更多
Dual-active-layer(DAL)amorphous InGaZnO(IGZO)thin-film transistors(TFTs)are fabricated at low temperature without post-annealing.A bottom low-resistance(low-R)IGZO layer and a top high-resistance(high-R)IGZO layer con...Dual-active-layer(DAL)amorphous InGaZnO(IGZO)thin-film transistors(TFTs)are fabricated at low temperature without post-annealing.A bottom low-resistance(low-R)IGZO layer and a top high-resistance(high-R)IGZO layer constitute the DAL homojunction with smooth and high-quality interface by in situ modulation of oxygen composition.The performance of the DAL TFT is significantly improved when compared to that of a single-active-layer TFT.A detailed investigation was carried out regarding the effects of the thickness of both layers on the electrical properties and gate bias stress stabilities.It is found that the low-R layer improves the mobility,ON/OFF ratio,threshold voltage and hysteresis voltage by passivating the defects and providing a smooth interface.The high-R IGZO layer has a great impact on the hysteresis,which changes from clockwise to counterclockwise.The best TFT shows a mobility of 5.41 cm^2/V·s,a subthreshold swing of 95.0 mV/dec,an ON/OFF ratio of 6.70×10^7,a threshold voltage of 0.24 V,and a hysteresis voltage of 0.13 V.The value of threshold voltage shifts under positive gate bias stress decreases when increasing the thickness of both layers.展开更多
Polarization-sensitive photodetection and imaging have great application value in fields such as polarization division multiplexing optical communication,remote sensing,near-field imaging and military monitoring.Pursu...Polarization-sensitive photodetection and imaging have great application value in fields such as polarization division multiplexing optical communication,remote sensing,near-field imaging and military monitoring.Pursuing a high polarization ratio has always been the research hotspot in polarization-sensitive photodetectors.In this paper,we report a compression strain enhanced polarization ratio inβ-gallium oxide(β-Ga_(2)O_(3))single crystal flake.A rigorous crystallographic analysis confirmed its high crystalline quality and orientation.Angle-resolved polarization Raman spectroscopy(ARPRS)was adopted to study the anisotropy of its optical properties.Extensive ARPRS measurements and theoretical calculation consistently demonstrate the strong optical anisotropy in the high-qualityβ-Ga_(2)O_(3)flake.A polarization ratio of 0.96 was obtained in the flatβ-Ga_(2)O_(3)flake.Furthermore,mechanical strain of±0.7%was introduced intoβ-Ga_(2)O_(3).An increased polarization ratio of 0.98 was achieved in the case of 0.7%compression strain,which is,to the best of our knowledge,the highest value for UVC polarization-sensitive photodetectors.That corresponds to an improved polarization rejection ratio of 100.This work proposed a new path towards improving polarization sensitivity by applying strain engineering in the active material.展开更多
Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))has been attracting more and more attention due to its unique merits such as wide bandgap(∼4.9 eV),low growth temperature,large-scale uniformity,low cost and energy efficient,makin...Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))has been attracting more and more attention due to its unique merits such as wide bandgap(∼4.9 eV),low growth temperature,large-scale uniformity,low cost and energy efficient,making it a powerful competitor in flexible deep ultraviolet(UV)photodetection.Although the responsivity of the ever-reported a-Ga_(2)O_(3)UV photodetectors(PDs)is usually in the level of hundreds of A/W,it is often accompanied by a large dark current due to the presence of abundant oxygen vacancy(VO)defects,which severely limits the possibility to detect weak signals and achieve versatile applications.In this work,the VO defects in a-Ga_(2)O_(3)thin films are successfully passivated by in-situ hydrogen doping during the magnetron sputtering process.As a result,the dark current of a-Ga_(2)O_(3)UV PD is remarkably suppressed to 5.17×10^(-11) A at a bias of 5 V.Importantly,the photocurrent of the corresponding device is still as high as 1.37×10^(-3)A,leading to a high photo-to-dark current ratio of 2.65×107 and the capability to detect the UV light with the intensity below 10 nW cm^(-2).Moreover,the H-doped a-Ga_(2)O_(3)thin films have also been deposited on polyethylene naphtholate substrates to construct flexible UV PDs,which exhibit no great degradation in bending states and fatigue tests.These results demonstrate that hydrogen doping can effectively improve the performance of a-Ga_(2)O_(3)UV PDs,further promoting its practical application in various areas.展开更多
Semiconductor solar-blind(220-280 nm)photodetectors(PDs),which have important applications both in civil and military aspects,are mainly based on diamond[1],Al Ga N[2],Mg Zn O[3],and Ga_2O_3[4-11].Among these material...Semiconductor solar-blind(220-280 nm)photodetectors(PDs),which have important applications both in civil and military aspects,are mainly based on diamond[1],Al Ga N[2],Mg Zn O[3],and Ga_2O_3[4-11].Among these materials,Ga_2O_3has a direct band gap(~4.9 e V)just falling in solarblind spectral range,which makes Ga_2O_3a desirable candidate for solar-blind photodetection.Up to now,many kinds of Ga_2O_3PDs have been demonstrated including bulk[4,5],film[6-8]and nanostructures[9-11],as summarized in Table 1.From the summary,we can see although bulk展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62174113,12174275,and 61874139)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2019B1515120057,2023A1515140094,and 2023A1515110730)。
文摘In the era of Internet of Things(Io Ts),an energy-efficient ultraviolet(UV)photodetector(PD)is highly desirable considering the massive usage scenarios such as environmental sterilization,fire alarm and corona discharge monitoring.So far,common self-powered UV PDs are mainly based on metal-semiconductor heterostructures or p–n heterojunctions,where the limited intrinsic built-in electric field restricts further enhancement of the photoresponsivity.In this work,an extremely low-voltage field-effect UV PD is proposed using a gatedrain shorted amorphous IGZO(a-IGZO)thin film transistor(TFT)architecture.A combined investigation of the experimental measurements and technology computer-aided design(TCAD)simulations suggests that the reverse current(ⅠR)of field-effect diode(FED)is highly related with the threshold voltage(Vth)of the parental TFT,implying an enhancement-mode TFT is preferable to fabricate the field-effect UV PD with low dark current.Driven by a low bias of-0.1 V,decent UV response has been realized including large UV/visible(R_(300)/R_(550))rejection ratio(1.9×10^(3)),low dark current(1.15×10^(-12)A)as well as high photo-to-dark current ratio(PDCR,~10^(3))and responsivity(1.89 A/W).This field-effect photodiode provides a new platform to construct UV PDs with well-balanced photoresponse performance at a low bias,which is attractive for designs of large-scale smart sensor networks with high energy efficiency.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674405,61874139,and 11675280)
文摘Dual-active-layer(DAL)amorphous InGaZnO(IGZO)thin-film transistors(TFTs)are fabricated at low temperature without post-annealing.A bottom low-resistance(low-R)IGZO layer and a top high-resistance(high-R)IGZO layer constitute the DAL homojunction with smooth and high-quality interface by in situ modulation of oxygen composition.The performance of the DAL TFT is significantly improved when compared to that of a single-active-layer TFT.A detailed investigation was carried out regarding the effects of the thickness of both layers on the electrical properties and gate bias stress stabilities.It is found that the low-R layer improves the mobility,ON/OFF ratio,threshold voltage and hysteresis voltage by passivating the defects and providing a smooth interface.The high-R IGZO layer has a great impact on the hysteresis,which changes from clockwise to counterclockwise.The best TFT shows a mobility of 5.41 cm^2/V·s,a subthreshold swing of 95.0 mV/dec,an ON/OFF ratio of 6.70×10^7,a threshold voltage of 0.24 V,and a hysteresis voltage of 0.13 V.The value of threshold voltage shifts under positive gate bias stress decreases when increasing the thickness of both layers.
基金supported by the National Natural Science Foundation of China(Grant Nos.61505109,12174275,62174113,and 11974108)Youth Innovative Talents Attracting and Cultivating Plan of Colleges and Universities in Shandong Province(No.21)+2 种基金Youth Innovation Team of Colleges and Universities in Shandong Province(Grant No.2022KJ223)Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515110607)Shandong Provincial Natural Science Foundation(Grant Nos.ZR2021QF020,ZR2022QF055,and ZR2021QE080)。
文摘Polarization-sensitive photodetection and imaging have great application value in fields such as polarization division multiplexing optical communication,remote sensing,near-field imaging and military monitoring.Pursuing a high polarization ratio has always been the research hotspot in polarization-sensitive photodetectors.In this paper,we report a compression strain enhanced polarization ratio inβ-gallium oxide(β-Ga_(2)O_(3))single crystal flake.A rigorous crystallographic analysis confirmed its high crystalline quality and orientation.Angle-resolved polarization Raman spectroscopy(ARPRS)was adopted to study the anisotropy of its optical properties.Extensive ARPRS measurements and theoretical calculation consistently demonstrate the strong optical anisotropy in the high-qualityβ-Ga_(2)O_(3)flake.A polarization ratio of 0.96 was obtained in the flatβ-Ga_(2)O_(3)flake.Furthermore,mechanical strain of±0.7%was introduced intoβ-Ga_(2)O_(3).An increased polarization ratio of 0.98 was achieved in the case of 0.7%compression strain,which is,to the best of our knowledge,the highest value for UVC polarization-sensitive photodetectors.That corresponds to an improved polarization rejection ratio of 100.This work proposed a new path towards improving polarization sensitivity by applying strain engineering in the active material.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022A1515110607 and 2019B1515120057)the National Natural Science Foundation of China(Grant Nos.62174113,12174275,61874139,61904201 and 11875088).
文摘Amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))has been attracting more and more attention due to its unique merits such as wide bandgap(∼4.9 eV),low growth temperature,large-scale uniformity,low cost and energy efficient,making it a powerful competitor in flexible deep ultraviolet(UV)photodetection.Although the responsivity of the ever-reported a-Ga_(2)O_(3)UV photodetectors(PDs)is usually in the level of hundreds of A/W,it is often accompanied by a large dark current due to the presence of abundant oxygen vacancy(VO)defects,which severely limits the possibility to detect weak signals and achieve versatile applications.In this work,the VO defects in a-Ga_(2)O_(3)thin films are successfully passivated by in-situ hydrogen doping during the magnetron sputtering process.As a result,the dark current of a-Ga_(2)O_(3)UV PD is remarkably suppressed to 5.17×10^(-11) A at a bias of 5 V.Importantly,the photocurrent of the corresponding device is still as high as 1.37×10^(-3)A,leading to a high photo-to-dark current ratio of 2.65×107 and the capability to detect the UV light with the intensity below 10 nW cm^(-2).Moreover,the H-doped a-Ga_(2)O_(3)thin films have also been deposited on polyethylene naphtholate substrates to construct flexible UV PDs,which exhibit no great degradation in bending states and fatigue tests.These results demonstrate that hydrogen doping can effectively improve the performance of a-Ga_(2)O_(3)UV PDs,further promoting its practical application in various areas.
基金supported by the National Natural Science Foundation of China (Grants Nos. 11674405, 11675280, 51272280, 11274366, 11474337, and 61306011)
文摘Semiconductor solar-blind(220-280 nm)photodetectors(PDs),which have important applications both in civil and military aspects,are mainly based on diamond[1],Al Ga N[2],Mg Zn O[3],and Ga_2O_3[4-11].Among these materials,Ga_2O_3has a direct band gap(~4.9 e V)just falling in solarblind spectral range,which makes Ga_2O_3a desirable candidate for solar-blind photodetection.Up to now,many kinds of Ga_2O_3PDs have been demonstrated including bulk[4,5],film[6-8]and nanostructures[9-11],as summarized in Table 1.From the summary,we can see although bulk