A study and control of lattice sites of N and In/Ga interdiffusion in dilute nitride quantum wells

Abstract

We studied effects of the distribution of interstitial (N,) and substitutional nitrogen (N,) and In/Ga interdiffusion on optical properties of the dilute nitride quantum wells (QWs) and the ways of suppressing diffusion. Without annealing, the concentration of N, remained almost constant while N, was linearly dependent on the total number of N. After annealing, the N, can be removed dramatically, and interdiffusion between In and Ga was found. Inserting a thin In, , /Ga, , , jN,yjAsj , , j / layer on either side of an In,-,jGaj ,- / NAsp ,. / QW (xq>xd) appears to suppress this interdiffusion. As a consequence. a blue shift of the photoluminescence signal after annealing remained small and the optical activity was largely improved. It was also found that a small amount of N incorporated in InGaAs QWs embedded in GaAs increased the In/Ga interdiffusion and that increased mechanical stresses enhanced the interdiffusion.