A confined structure in all three dimensions leads to carrier’s discrete energy level spectrum in quantum dots. This property has profound impact on many applications, such as single electron transistors, quantum dot laser, high efficiency photovoltaic cells, information storage etc. A finite element method is utilized to model the residual stress distribution. The effect of residual stress on the electronic and optical properties is studied. This is accomplished by incorporating both the valence subbands and the strain-induced potential field into Schrödinger equation. A finite-difference method was applied to solve the equation system. The density of states is obtained from the spectrum of the eigenstates. The discrete eigenstate distributions for both with and without residual stress are compared. The effect of the quantum dot size and geometry to the energy state distribution is discussed.

Numerical Simulation of electronic properties in quantum dot heterostructures

Three-dimensional InAs/GaAs quantum ring is studied under the energy dependent quasi-particle effective mass approximation. The confined energy problem is solved numerically by the finite element kp-perturbation method in a single subband approach. The influence of the quantum ring geometry on energy states and the electron effective mass is investigated. Model limitations are discussed.

Energy dependent effective mass model of InAs/GaAs quantum ring

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