Enhancement of the excitonic photoluminescence in n+/i-GaAs by controlling the thickness and impurity concentration of the n+ layer

Abstract

This communication presents the photoluminescence spectra of molecular beam epitaxially grown GaAs structures made from a 500 nm thick layer of intrinsic conductivity capped with a silicon doped layer with a film thickness ranging from 10 to 100 nm. Two different doping concentrations of the cap layer, NSi = 1017 cm-3 and NSi = 1018 cm-3, was considered. The results showed the excitonic line of i-GaAs layer enhancement. The intensity of excitonic line was about 160 times higher for the homojunction compared to the intrinsic conductivity epitaxial layer at liquid helium temperature. Possible mechanisms of the observed intensity enhancement in the n+/i-GaAs homojunction are discussed.