Optical properties in p-type doping of nitrides quaternary alloys multiple quantum wells

Abstract

Recent progress in the development of materials and devices, based on nitrides semiconductors and their ternary alloys, for high power, high-temperature applications has been remarkable. The AlInGaN quaternary alloy exhibits interesting features, as its emission intensity is higher than the ternary AlGaN alloy for certain Al compositions. In addition, it is possible to reach the near to ultraviolet (UV) region. Highly conductive p-type GaN, AlN and AlInGaN layers are of crucial importance in particular for some electronic and optoelectronic devices. However, the controlled doping and its efficiency have been difficult to obtain due to the deep nature of the Mg acceptor. Besides, very little has been reported on the electronic and optical properties of p-doped h-nitride quantum wells. In this work, photoluminescence and absorption spectra calculations of h-InGaN/AlInGaN and AlInGaN/InGaN multiple quantum wells (MQWs) have been performed by using the k.p theory within the effective mass approximation. The calculations are carried out by solving self-consistently the 8×8 Kane Hamiltonian together with the Poisson equation for the carriers charge density. Exchange-correlation effects are included within the local density approximation. In our calculations, strain effects due to lattice mismatch and the split-off hole band are taken into account. The Stokes shift, due to many-body effects within the quasi two-dimensional hole gas (2DHG), are also presented.