The paper reported the design and thorough analysis of a thin-film solar cell (TFSC) based on molybdenum disulfide (MoS<sub>2</sub>) with an integrated Copper(I) Oxide (Cu<sub>2</sub>O) hole tr...The paper reported the design and thorough analysis of a thin-film solar cell (TFSC) based on molybdenum disulfide (MoS<sub>2</sub>) with an integrated Copper(I) Oxide (Cu<sub>2</sub>O) hole transport layer (HTL), employing the one-dimensional Solar Cell Capacitance Simulator (SCAPS-1D) software. By varying crucial parameters such as absorber layer thickness, doping density, and bulk defect density, as well as HTL thickness, doping concentration, and electron affinity, defect density at ZnO/absorber and absorber/Cu<sub>2</sub>O interfaces, and operating temperature, we explored key photovoltaic measures including open circuit voltage (Voc), short-circuit current density (Jsc), fill-factor (FF), and power conversion efficiency (PCE) of the hetero-junction solar cell. The study demonstrated an efficiency of 18.87% for the MoS<sub>2</sub> solar cell without HTL, while the proposed solar cell (SC) utilizing Cu<sub>2</sub>O HTL and optimized device structure exhibited a remarkable PCE of 26.70%. The outcomes derived from the present study offer valuable insights for the progress of a highly efficient and economically viable MoS<sub>2</sub> hetero-junction TFSC.展开更多
In this paper, the positive influence of a uni-traveling-carrier （UTC） structure to ease the contract between the respon- sivity and working speed of the InP-based double hetero-junction phototransistor （DHPT） is ...In this paper, the positive influence of a uni-traveling-carrier （UTC） structure to ease the contract between the respon- sivity and working speed of the InP-based double hetero-junction phototransistor （DHPT） is illustrated in detail. Different results under electrical bias, optical bias or combined electrical and optical bias are analyzed for an excellent UTC-DHPT performance. The results show that when the UTC-DHPT operates at three-terminal （3T） working mode with combined electrical bias and optical bias in base, it keeps a high optical responsivity of 34.72 A/W and the highest optical transition frequency of 120 GHz. The current gain of the 3T UTC-DHPT under 1.55-μm light illuminations reaches 62 dB. This indicates that the combined base electrical bias and optical bias of 3T UTC-DHPT can make sure that the UTC-DHPT provides high optical current gain and high optical transition frequency simultaneously.展开更多
Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to Ga...Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This “rectifying” effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit （VEPF） analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.展开更多
A fully-coupled model for a piezoelectric hetero-junction subjected to a pair of stresses is proposed by discarding the depletion layer approximation.The effect of mechanical loadings on PN junction performance is dis...A fully-coupled model for a piezoelectric hetero-junction subjected to a pair of stresses is proposed by discarding the depletion layer approximation.The effect of mechanical loadings on PN junction performance is discussed in detail.Numerical examples are carried out for a p-Si/ZnO-n hetero-junction under a pair of stresses acting on the ntype ZnO portion near the PN interface,where ZnO has the piezoelectric property while Si is not.It is found that the bottom of conduction band is lowered/raised near the two loading points due to the decrease/increase in the electron potential energy there induced by a tensile-stress mode via sucking in majority-carriers from two outside regions,which implies appearance of a potential barrier and a potential well near two loading points.Furthermore,the barrier height and well depth gradually become large with increasing tensile stress such that more and more electrons/holes are inhaled in loading region from the n-/p-zone,respectively.Conversely,rising/dropping of conduction band bottom is brought out near the two loading points by a compressive-stress mode due to the increase/decrease in the potential energy of electrons by pumping out the majority-carriers from the loading region to the two outside regions.Therefore,a potential well and a potential barrier are induced near the two loading points,such that more and more electrons/holes are driven away from the loading region to the n-zone/p-zone,respectively,with the increasing compressive stress.These effects are important to tune the carrier recombination rate near the PN interface.Thus,the present study possesses great referential significance to piezotronic devices.展开更多
文摘The paper reported the design and thorough analysis of a thin-film solar cell (TFSC) based on molybdenum disulfide (MoS<sub>2</sub>) with an integrated Copper(I) Oxide (Cu<sub>2</sub>O) hole transport layer (HTL), employing the one-dimensional Solar Cell Capacitance Simulator (SCAPS-1D) software. By varying crucial parameters such as absorber layer thickness, doping density, and bulk defect density, as well as HTL thickness, doping concentration, and electron affinity, defect density at ZnO/absorber and absorber/Cu<sub>2</sub>O interfaces, and operating temperature, we explored key photovoltaic measures including open circuit voltage (Voc), short-circuit current density (Jsc), fill-factor (FF), and power conversion efficiency (PCE) of the hetero-junction solar cell. The study demonstrated an efficiency of 18.87% for the MoS<sub>2</sub> solar cell without HTL, while the proposed solar cell (SC) utilizing Cu<sub>2</sub>O HTL and optimized device structure exhibited a remarkable PCE of 26.70%. The outcomes derived from the present study offer valuable insights for the progress of a highly efficient and economically viable MoS<sub>2</sub> hetero-junction TFSC.
基金Project supported by the National Natural Science Foundation of China(Grant No.61006044)the Natural Science Foundation of Beijing,China(Grant Nos.4122014 and 4142007)the Fund from the Beijing Municipal Education Committee,China(Grant No.KM200910005001)
文摘In this paper, the positive influence of a uni-traveling-carrier （UTC） structure to ease the contract between the respon- sivity and working speed of the InP-based double hetero-junction phototransistor （DHPT） is illustrated in detail. Different results under electrical bias, optical bias or combined electrical and optical bias are analyzed for an excellent UTC-DHPT performance. The results show that when the UTC-DHPT operates at three-terminal （3T） working mode with combined electrical bias and optical bias in base, it keeps a high optical responsivity of 34.72 A/W and the highest optical transition frequency of 120 GHz. The current gain of the 3T UTC-DHPT under 1.55-μm light illuminations reaches 62 dB. This indicates that the combined base electrical bias and optical bias of 3T UTC-DHPT can make sure that the UTC-DHPT provides high optical current gain and high optical transition frequency simultaneously.
文摘Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This “rectifying” effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit （VEPF） analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.
基金Project supported by the National Natural Science Foundation of China(Nos.11972164 and 12102141)。
文摘A fully-coupled model for a piezoelectric hetero-junction subjected to a pair of stresses is proposed by discarding the depletion layer approximation.The effect of mechanical loadings on PN junction performance is discussed in detail.Numerical examples are carried out for a p-Si/ZnO-n hetero-junction under a pair of stresses acting on the ntype ZnO portion near the PN interface,where ZnO has the piezoelectric property while Si is not.It is found that the bottom of conduction band is lowered/raised near the two loading points due to the decrease/increase in the electron potential energy there induced by a tensile-stress mode via sucking in majority-carriers from two outside regions,which implies appearance of a potential barrier and a potential well near two loading points.Furthermore,the barrier height and well depth gradually become large with increasing tensile stress such that more and more electrons/holes are inhaled in loading region from the n-/p-zone,respectively.Conversely,rising/dropping of conduction band bottom is brought out near the two loading points by a compressive-stress mode due to the increase/decrease in the potential energy of electrons by pumping out the majority-carriers from the loading region to the two outside regions.Therefore,a potential well and a potential barrier are induced near the two loading points,such that more and more electrons/holes are driven away from the loading region to the n-zone/p-zone,respectively,with the increasing compressive stress.These effects are important to tune the carrier recombination rate near the PN interface.Thus,the present study possesses great referential significance to piezotronic devices.
