Exciton properties of nanoscale heterostrucrures AlxGa1-xN/GaN/AlxGa1-xN

Abstract

For the heterostructures AlxGa1-x N/GaN/AlxGa1-x N with different thicknesses of the GaN quantum wells and AlxGa1-xN barriers, we use an exciton model, which includes the interaction of an electron and a hole with deformations of the crystal lattice and with built-in electrostatic fields. It is based on a 6-band hole Hamiltonian, as distinct from the variational approach. Exciton energy spectra and wave functions for the ground state and some excited states are found after a numerical diagonalization of the 6-band matrix hole Hamiltonian with an adaptive grid. The photoluminescence peak position, the exciton oscillator strengths and the exciton radiative lifetime have been investigated as a function of the thicknesses of quantum wells and barriers as well as of the concentration x of Al in the barrier .The developed theoretical approach has allowed us to interpret the position of the zero-phonon and one-phonon photoluminescence bands and to obtain the exciton radiative lifetime in a good agreement with experiment.