An investigation was made of the effects of the stoichiometry of SiOx and SiNx capping layers upon the band-gap energy shift which was introduced by impurity-free vacancy disordering of In0.2Ga0.8As/GaAs multiple quantum-well structures. The stoichiometry of the SiOx and SiNx capping layers was modified by varying the flow rate of SiH4, and Ar gas was used as the carrier gas for dilute SiH4 gas in order to eliminate any possible incorporation of N into the deposited film when N was used as the carrier gas. A blue-shift of the photoluminescence peak by up to 0.112eV was observed following rapid thermal annealing (950C, 50s) of samples capped with SiOx (provided with a SiH4 flow-rate of 20sccm). It was observed that the magnitude of the blue-shift increased with decreasing SiH4 flow-rate for the SiOx and SiNx capping layers because of an increased

porosity of the dielectric capping layers. The insertion of an intermediate GaAs cap layer reduced the band-gap energy shift, regardless of the SiOx or SiNx capping layer.

Dependence of Band Gap Energy Shift of In0.2Ga0.8As/GaAs Multiple Quantum Well Structures by Impurity-Free Vacancy Disordering on Stoichiometry of SiOx and SiNx Capping Layers. J.S.Yu, J.D.Song, Y.T.Lee, H.Lim: Journal of Applied Physics, 2002, 91[7], 4256-60