Effects of Quantum Confinement on Optical properties of InN/GaN Quantum dots

摘要

Quantum dot (QD) confine charge carriers which results in strongly localized wave functions (WF), discrete energy eigen values and remarkable physical and novel device properties. In this paper, three-dimensional confinement regions of InN are obtained on a wetting layer (WL) in a GaN semiconducting matrix. Different structures are approximated with the influence of WL. The main objectives are: 1) To study the electronic states of single QD structure with WL and the role of their size and shape in determining the WFs and their eigen energies. 2) To study the interaction of neighboring QDs and their properties of WFs. One band Schr?dinger equation in the effective mass approximation is used to compute the electronic states of QDs. Envelope function approximation with BenDaniel-Duke boundary condition is used in combination to Schr?dinger equation for the calculation of eigen energies. Eigen energies are solved for the quasi-bound states using an eigenvalue study. The transfer matrix method is used to study the quantum tunneling of InN WFs, which is a direct bandgap material, through neighbor barriers of GaN material. Varying the QD radius (lnm to 8 nm) decreases the ground state energy of three structures of QD. WL thickness is increased from 0.5 nm to 3 nm which results in decrease of the eigen energies. Quasi bound state, transmission coefficient and reflection coefficient for the conical QD system are simulated. Changing the barrier width (1 nm to 3 nm) promotes higher probability of electron WF to pass through barriers. Absorption coefficient calculated for the system is 10~5 μm~(-1).