Carbon n-δ-doping effects on electronic and optical properties in GaAs/AlGaAs HEMTs

Abstract

In this work, we investigate two different δ-doping effects (carbon (C) and silicon (Si)) on the electronic and optical properties of n-δ-doping AlGaAs/GaAs HEMTs structures grown by molecular beam epitaxy on (100) oriented GaAs substrates. Photoluminescence measurements, as function of the silicon and carbon δ-doping, are used to determine the relaxation processes of the electron and the hole in the GaAs channel. Low and room temperatures PL spectra show the optical transitions that occur between the fundamental states of electrons to holes in the GaAs channel. Using C-n-δ-doping improves the two-dimensional electron gas confinement and decrease defects densities in the GaAs channel. For global information on the carriers dynamics in the structures studied, we studied their interactions with the crystal lattice, thermal activation states defects, the doping activation through the analysis of evolution of the PL spectrum depending on the temperature. The bands structures and theoretical activated electron densities have been studied theoretically using the finite differences method to self-consistently and simultaneously solve Schrödinger and Poisson equations written within the Hartree approximation.