Based on the nonlinear drift-diffusion(NLDD)model,the coupled behavior between the mechanical and electrical fields in piezoelectric semiconductor(PS)PN junctions under two typical loading conditions is investigated.T...Based on the nonlinear drift-diffusion(NLDD)model,the coupled behavior between the mechanical and electrical fields in piezoelectric semiconductor(PS)PN junctions under two typical loading conditions is investigated.The governing equations for the general shell structure of the PS PN junction are derived within the framework of virtual work principles and charge continuity conditions.The distributions of the electromechanical coupling field are obtained by the Fourier series expansion and the differential quadrature method(DQM),and the nonlinearity is addressed with the iterative method.Several numerical examples are presented to investigate the effects of mechanical loading on the charge carrier transport characteristics.It is found that the barrier height of the heterojunction can be effectively modulated by mechanical loading.Furthermore,a nonlinearity index is introduced to quantify the influence of nonlinearity in the model.It is noted that,when the concentration difference between the two sides is considerable,the nonlinear results differ significantly from the linear results,thereby necessitating the adoption of the NLDD model.展开更多
通过密度泛函理论(DFT)计算预测了三种具有五元环特征构型的二维硼化物结构,即penta-B_(4)X_(2)(X=S,Se,Te)。计算结果表明,三种penta-B_(4)X_(2)结构均表现出了良好的热力学、动力学、热学和力学稳定性。从结构上来看,penta-B_(4)X_(2...通过密度泛函理论(DFT)计算预测了三种具有五元环特征构型的二维硼化物结构,即penta-B_(4)X_(2)(X=S,Se,Te)。计算结果表明,三种penta-B_(4)X_(2)结构均表现出了良好的热力学、动力学、热学和力学稳定性。从结构上来看,penta-B_(4)X_(2)结构中的B—X共价键以及B—B共价键的共存有助于五边形框架的结构稳定性。此外,三种单层结构都具有较高的面内杨氏模量(最低为90.67 Nm^(-1)),其中二维penta-B_(4)Se_(2)单层在特定面内角方向上具有负泊松比(NPR)。电子能带结构表明所有单层结构都具有适中带隙(1.04、1.17、1.28 e V)的半导体材料。三种二维pentaB_(4)X_(2)对于不同波段的光波均具有较强的吸收系数,可见光区最高可达3.5×10~5 cm^(-1)的数量级,紫外光区域则表现出更强的光吸收能力。优异的光吸收性能使得二维penta-B_(4)X_(2)结构成为潜在的光致水解材料。展开更多
The performance of a piecewise-stressed ZnO piezoelectric semiconductor nano?ber is studied with the multi-?eld coupling theory. The ?elds produced by equal and opposite forces as well as sinusoidally distributed forc...The performance of a piecewise-stressed ZnO piezoelectric semiconductor nano?ber is studied with the multi-?eld coupling theory. The ?elds produced by equal and opposite forces as well as sinusoidally distributed forces are examined. Speci?c distributions of potential barriers, wells, and regions with effective polarization charges are found. The results are fundamental for the mechanical tuning on piezoelectric semiconductor devices and piezotronics.展开更多
The electric band energy variation in a bent piezoelectric semiconductor(PSC) nanowire of circular cross-section induced by the mechanical force is analyzed based on a six-band k · p method. The electric-mechanic...The electric band energy variation in a bent piezoelectric semiconductor(PSC) nanowire of circular cross-section induced by the mechanical force is analyzed based on a six-band k · p method. The electric-mechanical fields are first obtained analytically in a cantilever bent PSC nanowire by solving the fully-coupled electro-mechanical equations. Then, the band energy is acquired numerically via the six-band Hamiltonian.By considering further the nonlinear coupling between the piezoelectric and semiconducting quantities, the contribution of the redistribution carriers to the electric field is analyzed from the Gauss’ s law. Numerical examples are carried out for an n-type Zn O nanowire in different locations induced by an applied concentrated end force. They include the electric potential, heavy hole(HH), light hole(LH), spin-orbit split-off(SO),and conduction band(CB) edges along the axial and thickness directions. Our results show that the applied force has a significant effect on the band energies. For instance, on the bottom surface along the axial direction, the bandgaps near the fixed end are greater than those near the loading end, and this trend is reversed on the top surface. Moreover,at a fixed axial location, the energy level of the lower side can be enhanced by applying a bending force at the end. The present results could be of significant guidance to the electronic devices and piezotronics.展开更多
Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtz...Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtzite structure ZnO nanofiber under the local mechanical loading. The energy band structure tuned by the local mechanical loading and local length is calculated via an eight-band k·p method, which includes the coupling of valance and conduction bands. Poisson's effect on the distribution of electric potential inversely depends on the local mechanical loading. Numerical results reveal that both the applied local mechanical loading and the local length exhibit obvious tuning effects on the electric potential and energy band. The band gap at band edges varies linearly with the applied loading. Changing the local length shifts the energy band which is far away from the band edges. This study will be useful in the electronic and optical enhancement of semiconductor devices.展开更多
基金supported by the National Key Research and Development Program of China(No.2023YFE0111000)the National Natural Science Foundation of China(Nos.12372151,12302200,12172171,12172183,and U24A2005)+6 种基金the Natural Science Foundation of Jiangsu Province of China(No.BK20230873)the China Postdoctoral Science Foundation(No.2023M731671)the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2023ZB156)the Shenzhen Science and Technology Program(No.JCYJ20230807142004009)the Jiangsu Association for Science&Technology Youth Science&Technology Talents Lifting Projectthe Russian Ministry of Science and Higher Education(No.075-15-2023-580)the Shenzhen Longhua Science and Technology Innovation Special Funding(Industrial Sci-Tech Innovation Center of Low-Altitude Intelligent Networking)。
文摘Based on the nonlinear drift-diffusion(NLDD)model,the coupled behavior between the mechanical and electrical fields in piezoelectric semiconductor(PS)PN junctions under two typical loading conditions is investigated.The governing equations for the general shell structure of the PS PN junction are derived within the framework of virtual work principles and charge continuity conditions.The distributions of the electromechanical coupling field are obtained by the Fourier series expansion and the differential quadrature method(DQM),and the nonlinearity is addressed with the iterative method.Several numerical examples are presented to investigate the effects of mechanical loading on the charge carrier transport characteristics.It is found that the barrier height of the heterojunction can be effectively modulated by mechanical loading.Furthermore,a nonlinearity index is introduced to quantify the influence of nonlinearity in the model.It is noted that,when the concentration difference between the two sides is considerable,the nonlinear results differ significantly from the linear results,thereby necessitating the adoption of the NLDD model.
文摘通过密度泛函理论(DFT)计算预测了三种具有五元环特征构型的二维硼化物结构,即penta-B_(4)X_(2)(X=S,Se,Te)。计算结果表明,三种penta-B_(4)X_(2)结构均表现出了良好的热力学、动力学、热学和力学稳定性。从结构上来看,penta-B_(4)X_(2)结构中的B—X共价键以及B—B共价键的共存有助于五边形框架的结构稳定性。此外,三种单层结构都具有较高的面内杨氏模量(最低为90.67 Nm^(-1)),其中二维penta-B_(4)Se_(2)单层在特定面内角方向上具有负泊松比(NPR)。电子能带结构表明所有单层结构都具有适中带隙(1.04、1.17、1.28 e V)的半导体材料。三种二维pentaB_(4)X_(2)对于不同波段的光波均具有较强的吸收系数,可见光区最高可达3.5×10~5 cm^(-1)的数量级,紫外光区域则表现出更强的光吸收能力。优异的光吸收性能使得二维penta-B_(4)X_(2)结构成为潜在的光致水解材料。
基金Project supported by the National Natural Science Foundation of China(Nos.11672113 and 51435006)the Key Laboratory Project of Hubei Province of China(No.2016CFA073)
文摘The performance of a piecewise-stressed ZnO piezoelectric semiconductor nano?ber is studied with the multi-?eld coupling theory. The ?elds produced by equal and opposite forces as well as sinusoidally distributed forces are examined. Speci?c distributions of potential barriers, wells, and regions with effective polarization charges are found. The results are fundamental for the mechanical tuning on piezoelectric semiconductor devices and piezotronics.
基金Project supported by the National Natural Science Foundation of China(Nos.11972164,11672113,11472182)the Key Laboratory Project of Hubei Province of China(No.2016CFA073)。
文摘The electric band energy variation in a bent piezoelectric semiconductor(PSC) nanowire of circular cross-section induced by the mechanical force is analyzed based on a six-band k · p method. The electric-mechanical fields are first obtained analytically in a cantilever bent PSC nanowire by solving the fully-coupled electro-mechanical equations. Then, the band energy is acquired numerically via the six-band Hamiltonian.By considering further the nonlinear coupling between the piezoelectric and semiconducting quantities, the contribution of the redistribution carriers to the electric field is analyzed from the Gauss’ s law. Numerical examples are carried out for an n-type Zn O nanowire in different locations induced by an applied concentrated end force. They include the electric potential, heavy hole(HH), light hole(LH), spin-orbit split-off(SO),and conduction band(CB) edges along the axial and thickness directions. Our results show that the applied force has a significant effect on the band energies. For instance, on the bottom surface along the axial direction, the bandgaps near the fixed end are greater than those near the loading end, and this trend is reversed on the top surface. Moreover,at a fixed axial location, the energy level of the lower side can be enhanced by applying a bending force at the end. The present results could be of significant guidance to the electronic devices and piezotronics.
基金Project supported by the National Natural Science Foundation of China (No. 11802098)the Chinese Postdoctoral Science Foundation (No. 2019M662589)the Natural Science Foundation of Hubei Province of China (No. 2018CFB111)。
文摘Recent success in strain engineering has triggered tremendous interest in its study and potential applications in nanodevice design. In this paper, we establish a coupled piezoelectric/semiconducting model for a wurtzite structure ZnO nanofiber under the local mechanical loading. The energy band structure tuned by the local mechanical loading and local length is calculated via an eight-band k·p method, which includes the coupling of valance and conduction bands. Poisson's effect on the distribution of electric potential inversely depends on the local mechanical loading. Numerical results reveal that both the applied local mechanical loading and the local length exhibit obvious tuning effects on the electric potential and energy band. The band gap at band edges varies linearly with the applied loading. Changing the local length shifts the energy band which is far away from the band edges. This study will be useful in the electronic and optical enhancement of semiconductor devices.
