Low-cost and large-area uniform amorphous Ga_(2)O_(3)(α-Ga_(2)O_(3))solar-blind ultraviolet(UV)detectors have garnered significant attention in recent years.Oxygen vacancy(VO)defects are generally considered as the p...Low-cost and large-area uniform amorphous Ga_(2)O_(3)(α-Ga_(2)O_(3))solar-blind ultraviolet(UV)detectors have garnered significant attention in recent years.Oxygen vacancy(VO)defects are generally considered as the predominant defects affecting the detector performance.Reducing VOconcentration generally results in both low dark current and low photo current,significantly limiting further improvement of the photo-to-dark current ratio(PDCR)parameter.Herein,a delicately optimized atomic layer deposition(ALD)method is revealed having the capability to break through the trade-off in a-Ga_(2)O_(3),achieving both low dark current and high photocurrent simultaneously.For a clear demonstration,a-Ga_(2)O_(3)contrast sample is prepared by magnetron sputtering and compared as well.Combined tests are performed including xray photoelectron spectroscopy,photoluminescence,electron paramagnetic resonance and Fourier-transform infrared spectroscopy.It is found that ALDα-Ga_(2)O_(3)has a lower VOconcentration,but also a lower dangling bonds concentration which are strong non-irradiation recombination centers.Therefore,decrease of dangling bonds is suggested to compensate for the low optical gain induced by low VOconcentration and promote the PDCR to~2.06×10^(6).Our findings firstly prove that the dangling bonds also play an important role in determining the a-Ga_(2)O_(3)detection performance,offering new insights for further promotion ofα-Ga_(2)O_(3)UV detector performance via dual optimization of dangling bonds and VO.展开更多
A tunable,controllable,and reversible photoresponse within a single device holds significant potential for broad-spectrum image detection,convolutional computation,and autonomous systems.This study presents a novel gr...A tunable,controllable,and reversible photoresponse within a single device holds significant potential for broad-spectrum image detection,convolutional computation,and autonomous systems.This study presents a novel graphene-gated WSe_(2) heterojunction field-effect transistor(FET),utilizing graphene as a highly transparent gate electrode.By modulating the graphene-gated voltage,which affects the effective bias voltage,the current is redirected into both the graphene and metal electrodes along the WSe_(2).The device exhibits notable and adjustable positive photoconductance(V_(g)<3.25 V)and negative photoconductance(V_(g)>3.25 V)under 520 nm illumination.The responsivity of positive photocon-ductance(V_(g)=-5 V)and negative photoconductance(V_(g)=5 V)values are 427 and 425 mA/W,respectively.Additionally,the device demonstrates excellent performance,with a high fitting exponent(0.99)between power intensity and photocurrent at zero bias due to the photovoltaic effect.Leveraging its controllable and reversible photoresponse,along with the photovoltaic effect,the graphene-gated WSe_(2) heterojunction FET enables multifunctional applications,including encrypted communication,“OR”logic operations,three-state logic gates and imaging pre-processing.Besides,images can be pre-processed and enhanced by integrating convolutional neural networks.These findings highlight the promising potential of high-performance multifunctional optoelectronic devices.展开更多
Realization of positive and negative optical responses in a single device promises construction of multifunctional optoelectronic devices.This work demonstrates a Ga_(2)O_(3)∕WSe_(2) mixed-dimensional heterojunction ...Realization of positive and negative optical responses in a single device promises construction of multifunctional optoelectronic devices.This work demonstrates a Ga_(2)O_(3)∕WSe_(2) mixed-dimensional heterojunction junction fieldeffect transistor(JFET)with positive and negative photoresponse regulatory functions by gate voltage.The device achieves a remarkable negative responsivity exceeding 425 mA/W.Additionally,benefiting from Fowler-Nordheim tunneling(FNT)behavior,the mixed-dimensional JFET exhibited an excellent negative response performance with response and decay times of 50.1 ms and 53.9 ms and a high I OFF∕I ON ratio of 343 at V ds1 V and Vg5 V under 635 nm illumination.Additionally,the JFET’s negative photoresponse is sensitive to both gate voltage and light intensity,which can be used to realize NAND logic gate and optical communication functions.These results unveil the promising potential of mixed-dimensional optoelectronic devices for optical communication,and logic device technologies.展开更多
The high-quality semiconductor InGa ZnO(IGZO)alloy thin films with different indium(In)elemental contents were deposit utilized magnetron sputtering.The novel bilayer heterojunction TFT devices based on our fabricated...The high-quality semiconductor InGa ZnO(IGZO)alloy thin films with different indium(In)elemental contents were deposit utilized magnetron sputtering.The novel bilayer heterojunction TFT devices based on our fabricated IGZO films were proposed,and their performance exhibited significant improvement compared to single layer IGZO TFTs.In the bilayer heterojunction TFT,the field-effect mobility was promoted to 23.5 cm^(2)·V^(-1)·s^(-1),the switching ratio reached 4.1×10^(7),and the subthreshold swing was reduced to 0.42 V/dec.Moreover,the variation of bilayer TFTs threshold voltage(Vth)was significantly suppressed,Under positive gate bias stress(PBS)and negative gate bias stress(NBS),the threshold shift is reduced to be 1.5 V and-1.1 V,respectively.The heterojunction within the bilayer IGZO films constructs a potential barrier at the interface,which facilitated the accumulation of channel electrons.Additionally,the low In-element content passivation layer in IGZO films not only preserved the channel of TFT but also reduced electron scattering,thereby the performance properties of TFT were enhancing.The excellent transistor characteristics of devices demonstrate the feasibility of our proposed bilayer heterojunction TFT,which will promote the basic research of IGZO device and accelerate the practical application of transparency IGZO TFT.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62404146,12174275,62174113)the Basic and Applied Basic Research Foundation of Guangdong Province,China(Grant Nos.2023A1515110730 and 2023A1515140094)the INTPART Program at the Research Council of Norway(Project number 322382)。
文摘Low-cost and large-area uniform amorphous Ga_(2)O_(3)(α-Ga_(2)O_(3))solar-blind ultraviolet(UV)detectors have garnered significant attention in recent years.Oxygen vacancy(VO)defects are generally considered as the predominant defects affecting the detector performance.Reducing VOconcentration generally results in both low dark current and low photo current,significantly limiting further improvement of the photo-to-dark current ratio(PDCR)parameter.Herein,a delicately optimized atomic layer deposition(ALD)method is revealed having the capability to break through the trade-off in a-Ga_(2)O_(3),achieving both low dark current and high photocurrent simultaneously.For a clear demonstration,a-Ga_(2)O_(3)contrast sample is prepared by magnetron sputtering and compared as well.Combined tests are performed including xray photoelectron spectroscopy,photoluminescence,electron paramagnetic resonance and Fourier-transform infrared spectroscopy.It is found that ALDα-Ga_(2)O_(3)has a lower VOconcentration,but also a lower dangling bonds concentration which are strong non-irradiation recombination centers.Therefore,decrease of dangling bonds is suggested to compensate for the low optical gain induced by low VOconcentration and promote the PDCR to~2.06×10^(6).Our findings firstly prove that the dangling bonds also play an important role in determining the a-Ga_(2)O_(3)detection performance,offering new insights for further promotion ofα-Ga_(2)O_(3)UV detector performance via dual optimization of dangling bonds and VO.
基金the National Natural Science Foundation of China(Nos.11974122 and U22A2073)the Scientific and Technological Plan of Guangdong Province,China(No.2022A0505050067)+2 种基金the Open Research Project Programme of the Macao Centre for Research and Development in Advanced Materials(University of Macao)(No.MCRDAM-IAPME(UM)-2022-2024/ORP/XXX/2023)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515011242)the Scientific Research Innovation Project of Graduate School of South China Normal University.
文摘A tunable,controllable,and reversible photoresponse within a single device holds significant potential for broad-spectrum image detection,convolutional computation,and autonomous systems.This study presents a novel graphene-gated WSe_(2) heterojunction field-effect transistor(FET),utilizing graphene as a highly transparent gate electrode.By modulating the graphene-gated voltage,which affects the effective bias voltage,the current is redirected into both the graphene and metal electrodes along the WSe_(2).The device exhibits notable and adjustable positive photoconductance(V_(g)<3.25 V)and negative photoconductance(V_(g)>3.25 V)under 520 nm illumination.The responsivity of positive photocon-ductance(V_(g)=-5 V)and negative photoconductance(V_(g)=5 V)values are 427 and 425 mA/W,respectively.Additionally,the device demonstrates excellent performance,with a high fitting exponent(0.99)between power intensity and photocurrent at zero bias due to the photovoltaic effect.Leveraging its controllable and reversible photoresponse,along with the photovoltaic effect,the graphene-gated WSe_(2) heterojunction FET enables multifunctional applications,including encrypted communication,“OR”logic operations,three-state logic gates and imaging pre-processing.Besides,images can be pre-processed and enhanced by integrating convolutional neural networks.These findings highlight the promising potential of high-performance multifunctional optoelectronic devices.
基金National Natural Science Foundation of China(11974122,U22A2073)Science and Technology Planning Project of Guangdong Province(2022A0505050067)+1 种基金Open Research Project Programme of the Macao Centre for Research and Development in Advanced Materials(University of Macao)(MCRDAM-IAPME(UM)-2022-2024/ORP/XXX/2023)Scientific Research Innovation Project of Graduate School of South China Normal University.
文摘Realization of positive and negative optical responses in a single device promises construction of multifunctional optoelectronic devices.This work demonstrates a Ga_(2)O_(3)∕WSe_(2) mixed-dimensional heterojunction junction fieldeffect transistor(JFET)with positive and negative photoresponse regulatory functions by gate voltage.The device achieves a remarkable negative responsivity exceeding 425 mA/W.Additionally,benefiting from Fowler-Nordheim tunneling(FNT)behavior,the mixed-dimensional JFET exhibited an excellent negative response performance with response and decay times of 50.1 ms and 53.9 ms and a high I OFF∕I ON ratio of 343 at V ds1 V and Vg5 V under 635 nm illumination.Additionally,the JFET’s negative photoresponse is sensitive to both gate voltage and light intensity,which can be used to realize NAND logic gate and optical communication functions.These results unveil the promising potential of mixed-dimensional optoelectronic devices for optical communication,and logic device technologies.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A2073 and 62474197)the Basic and Applied Basic Research Foundation of Guangdong Province,China(Grant Nos.2024A1515011536 and 2025A04J7142)。
文摘The high-quality semiconductor InGa ZnO(IGZO)alloy thin films with different indium(In)elemental contents were deposit utilized magnetron sputtering.The novel bilayer heterojunction TFT devices based on our fabricated IGZO films were proposed,and their performance exhibited significant improvement compared to single layer IGZO TFTs.In the bilayer heterojunction TFT,the field-effect mobility was promoted to 23.5 cm^(2)·V^(-1)·s^(-1),the switching ratio reached 4.1×10^(7),and the subthreshold swing was reduced to 0.42 V/dec.Moreover,the variation of bilayer TFTs threshold voltage(Vth)was significantly suppressed,Under positive gate bias stress(PBS)and negative gate bias stress(NBS),the threshold shift is reduced to be 1.5 V and-1.1 V,respectively.The heterojunction within the bilayer IGZO films constructs a potential barrier at the interface,which facilitated the accumulation of channel electrons.Additionally,the low In-element content passivation layer in IGZO films not only preserved the channel of TFT but also reduced electron scattering,thereby the performance properties of TFT were enhancing.The excellent transistor characteristics of devices demonstrate the feasibility of our proposed bilayer heterojunction TFT,which will promote the basic research of IGZO device and accelerate the practical application of transparency IGZO TFT.
