This article puts forward a new method in calculating the band structures of low-dimensional semiconductor structures. In this study, the valence band structures of InAs/GaAs quantum ring and lens-shaped quantum dot a...This article puts forward a new method in calculating the band structures of low-dimensional semiconductor structures. In this study, the valence band structures of InAs/GaAs quantum ring and lens-shaped quantum dot are calculated with four-band model, in the framework of effective-mass envelope function theory. To determine the Hamiltonian matrix elements, this article develops the numerical Fourier transform method instead of the widely used analytical integral method. The valence band mixing is considered. The hole energy levels change dramatically with the geometrical parameters of the quantum ring and quantum dot. It is demonstrated that numerical Fourier transform method can be adopted in low-dimensional structures with any shape. The results of Fourier transform method are consistent with the ones of analytical integral in literature; and they are helpful for studying and fabricating optoelectronic devices.展开更多
The valence band structure and hole effective mass of silicon under a uniaxial stress in （001） surface along the [110] direction were detailedly investigated in the framework of the k. p theory. The results demonstr...The valence band structure and hole effective mass of silicon under a uniaxial stress in （001） surface along the [110] direction were detailedly investigated in the framework of the k. p theory. The results demonstrated that the splitting energy between the top band and the second band for tmiaxial compressive stress is bigger than that of the tensile one at the same stress magnitude, and of all common used crystallographic direction, such as [110], [001], [110] and [100], the effective mass for the top band along [110] crystallographic direction is lower under uniaxial compressive stress compared with other stresses and crystallographic directions configurations. In view of suppressing the scattering and reducing the effective mass, the [110] crystallographic direction is most favorable to be used as transport direction of the charge carrier to enhancement mobility when a uniaxial compressive stress along [110] direction is applied. The obtained results can provide a theory reference for the design and the selective of optimum stress and crystallorgraphic direction configuration ofuniaxial strained silicon devices.展开更多
基金supported by the Hi-Tech Research and Development Program of China (2009AA03Z405)the National Natural Science Foundation of China (60908028)+1 种基金the National Natural Science Foundation of China (60971068)the High School Innovation and Introducing Talent Project of China (B07005)
文摘This article puts forward a new method in calculating the band structures of low-dimensional semiconductor structures. In this study, the valence band structures of InAs/GaAs quantum ring and lens-shaped quantum dot are calculated with four-band model, in the framework of effective-mass envelope function theory. To determine the Hamiltonian matrix elements, this article develops the numerical Fourier transform method instead of the widely used analytical integral method. The valence band mixing is considered. The hole energy levels change dramatically with the geometrical parameters of the quantum ring and quantum dot. It is demonstrated that numerical Fourier transform method can be adopted in low-dimensional structures with any shape. The results of Fourier transform method are consistent with the ones of analytical integral in literature; and they are helpful for studying and fabricating optoelectronic devices.
基金Project supported by the National Ministries and Commissions of China(Nos.51308040203,6139801)the Fundamental Research Funds for the Central Universities of China(No.72105499)the Natural Science Basic Research Plan in Shaanxi Province of China(No. 2010JQ8008)
文摘The valence band structure and hole effective mass of silicon under a uniaxial stress in （001） surface along the [110] direction were detailedly investigated in the framework of the k. p theory. The results demonstrated that the splitting energy between the top band and the second band for tmiaxial compressive stress is bigger than that of the tensile one at the same stress magnitude, and of all common used crystallographic direction, such as [110], [001], [110] and [100], the effective mass for the top band along [110] crystallographic direction is lower under uniaxial compressive stress compared with other stresses and crystallographic directions configurations. In view of suppressing the scattering and reducing the effective mass, the [110] crystallographic direction is most favorable to be used as transport direction of the charge carrier to enhancement mobility when a uniaxial compressive stress along [110] direction is applied. The obtained results can provide a theory reference for the design and the selective of optimum stress and crystallorgraphic direction configuration ofuniaxial strained silicon devices.
