Numerical Simulation of Electronic Properties in Quantum Dot Hheterostructures
B. Vlahovic, I. Filikhin, V.M. Suslov and K. Wang
North Carolina Central University, US
Keywords: quantum dots, residual stress, energy level
Because of the strong dependence of energy level on the geometry and sizes, the quantum dots are perfect candidates as high efficiency photovoltaic solar cells. Efficiency of 63.2% solar cell has been predicted by theoretical work. A finite element method has been utilized to model the residual stress distribution. The effects of lattice mismatch, thermal expansion, and geometry of the sample have been systematically studied. A finite difference method was then applied to model the electronic properties of quantum dots. The effects of residual stresses on the electronic and optical properties are also studied. This was accomplished by incorporating both the valence subbands and the strain-induced potential field into the time-independent Schrödinger equation. Finite-difference method was applied to solve the equation system. The density of states is obtained from the spectrum of the eigenstates in the numerical solutions. Calculations have been performed on a series of quantum dots with different size and geometries. The discrete distributions for both with and without residual stresses are compared. The impact of residual stress is clearly observed. Detail results on various size and geometry will be provided.
Nanotech 2004 Conference Technical Program Abstract