A high-performance heterojunction photodetector is formed by combining an n-type Si substrate with p-type monolayer WSe2 obtained using physical vapor deposition. The high quality of the WSe2/Si heterojunction is demo...A high-performance heterojunction photodetector is formed by combining an n-type Si substrate with p-type monolayer WSe2 obtained using physical vapor deposition. The high quality of the WSe2/Si heterojunction is demonstrated by the suppressed dark current of I nA and the extremely high rectification ratio of 107. Under illumination, the heterojunction exhibits a wide photoresponse range from ultraviolet to near-infrared radiation. The introduction of graphene quantum dots （GQDs） greatly elevates the photodetective capabilities of the heterojunction with strong light absorption and long carrier lifetimes. The GQDs/WSe2/Si heterojunction exhibits a high responsivity of -707 mA·W^-1, short response time of 0.2 ms, and good specific detectivity of -4.51×10^9 Jones. These properties suggest that the GQDs/WSe2/Si heterojunction holds great potential for application in future high- performance photodetectors.展开更多
Controlled synthesis of structurally anisotropic rhenium diselenide （ReSe2） with macroscopically uniform and strictly monolayer thickness as well as tunable domain shape/size is of great interest for electronics-, o...Controlled synthesis of structurally anisotropic rhenium diselenide （ReSe2） with macroscopically uniform and strictly monolayer thickness as well as tunable domain shape/size is of great interest for electronics-, optoelectronics-, and electrocatalysis-related applications. Herein, we describe the controlled synthesis of uniform monolayer ReSe2 flakes with variable morphology （sunflower- or truncated-triangle-shaped） on SiO2/Si substrates using different ambient-pressure chemical vapor deposition （CVD） setups. The prepared polycrystalline ReSe2 flakes were transferred intact onto Au foil electrodes and tested for activity in the hydrogen evolution reaction （HER）. Interestingly, compared to the compact truncated-triangle-shaped ReSe2 flakes, their edge-abundant sunflower-shaped counterparts exhibited superior electrocatalytic HER activity, featuring a relatively low Tafel slope of - 76 mV/dec and an exchange current density of 10.5 μA/cm2. Thus, our work demonstrates that CVD-grown ReSe2 is a promising two- dimensional anisotropic material for applications in the electrocatalytic HER.展开更多
Heterogeneous complementary inverters composed of bi-layer molybdenum disulfide （MoS2） and single-walled carbon-nanotube （SWCNT） networks are designed, and n-type MoS2/p-type SWCNT inverters are fabricated with a ...Heterogeneous complementary inverters composed of bi-layer molybdenum disulfide （MoS2） and single-walled carbon-nanotube （SWCNT） networks are designed, and n-type MoS2/p-type SWCNT inverters are fabricated with a backgated structure. Field-effect transistors （FETs） based on the MoS2 and SWCNT networks show high electrical performance with large ON/OFF ratios up to 106 and 105 for MoS2 and SWCNT, respectively. The MoS2/SWCNT complementary inverters exhibit Vin-Vout signal matching and achieve excellent performances with a high peak voltage gain of 15, a low static-power consumption of a few nanowatts, and a high noise margin of 0.45VDD, which are suitable for future logic-circuit applications. The inverter performances are affected by the channel width-to-length ratios （W/L） of the MOSR-FETs and SWCNT-FETs. Therefore, W/L should be optimized to achieve a tradeoff between the gain and the power consumption.展开更多
文摘A high-performance heterojunction photodetector is formed by combining an n-type Si substrate with p-type monolayer WSe2 obtained using physical vapor deposition. The high quality of the WSe2/Si heterojunction is demonstrated by the suppressed dark current of I nA and the extremely high rectification ratio of 107. Under illumination, the heterojunction exhibits a wide photoresponse range from ultraviolet to near-infrared radiation. The introduction of graphene quantum dots （GQDs） greatly elevates the photodetective capabilities of the heterojunction with strong light absorption and long carrier lifetimes. The GQDs/WSe2/Si heterojunction exhibits a high responsivity of -707 mA·W^-1, short response time of 0.2 ms, and good specific detectivity of -4.51×10^9 Jones. These properties suggest that the GQDs/WSe2/Si heterojunction holds great potential for application in future high- performance photodetectors.
基金The work was supported by the National Natural Science Foundation of China （Nos. 51290272, 51472008, 21573004, 51522212, 51421002, 51672154, 51372130, and 51672307）, the National Key Technologies Research and Development Program of China （No. 2016YFA0200103）, the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics （No. KF201601）, the National Program on Key Basic Research Project （No. 2014CB921002）, the Strategic Priority Research Program of Chinese Academy of Sciences （No. XDB07030200）, the Key Research Program of Frontier Sciences, CAS （No. QYZDB-SSW-JSC035）, and the MoST （2016YFA0200200）.
文摘Controlled synthesis of structurally anisotropic rhenium diselenide （ReSe2） with macroscopically uniform and strictly monolayer thickness as well as tunable domain shape/size is of great interest for electronics-, optoelectronics-, and electrocatalysis-related applications. Herein, we describe the controlled synthesis of uniform monolayer ReSe2 flakes with variable morphology （sunflower- or truncated-triangle-shaped） on SiO2/Si substrates using different ambient-pressure chemical vapor deposition （CVD） setups. The prepared polycrystalline ReSe2 flakes were transferred intact onto Au foil electrodes and tested for activity in the hydrogen evolution reaction （HER）. Interestingly, compared to the compact truncated-triangle-shaped ReSe2 flakes, their edge-abundant sunflower-shaped counterparts exhibited superior electrocatalytic HER activity, featuring a relatively low Tafel slope of - 76 mV/dec and an exchange current density of 10.5 μA/cm2. Thus, our work demonstrates that CVD-grown ReSe2 is a promising two- dimensional anisotropic material for applications in the electrocatalytic HER.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 51672154, 51372130, and 61401251）, Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics （No. KF201517）, and Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices （No. KFJJ201402）.
文摘Heterogeneous complementary inverters composed of bi-layer molybdenum disulfide （MoS2） and single-walled carbon-nanotube （SWCNT） networks are designed, and n-type MoS2/p-type SWCNT inverters are fabricated with a backgated structure. Field-effect transistors （FETs） based on the MoS2 and SWCNT networks show high electrical performance with large ON/OFF ratios up to 106 and 105 for MoS2 and SWCNT, respectively. The MoS2/SWCNT complementary inverters exhibit Vin-Vout signal matching and achieve excellent performances with a high peak voltage gain of 15, a low static-power consumption of a few nanowatts, and a high noise margin of 0.45VDD, which are suitable for future logic-circuit applications. The inverter performances are affected by the channel width-to-length ratios （W/L） of the MOSR-FETs and SWCNT-FETs. Therefore, W/L should be optimized to achieve a tradeoff between the gain and the power consumption.
