Ordering in strained Ga xIn 1− xP quantum wells grown by metalorganic vapor phase epitaxy

Abstract

Strained GaInP quantum wells with AlGaInP barriers have been grown by metalorganic vapor phase epitaxy (MOVPE). The influence of strain in single quantum wells on the optical properties is examined by photoluminescence. The emission energy of strongly compressively strained quantum wells shows an anomalous temperature dependence and a shift of 13 meV per decade of excitation power. This is interpreted as an accurate measure of the critical strain where strain relaxation occurs. By varying growth temperature and substrate orientation, the influence of ordering in strained and unstrained quantum wells is examined. Whereas unstrained quantum wells show a similar band gap reduction as bulk GaInP, this is significantly weakened in strained quantum wells. This has two reasons. For one, the degree of ordering is limited due to unequal Ga and In amounts. Additionally, according to Wei et al. [Appl. Phys. Lett. 64 (1994) 757], a further reduction is expected if the joint influence of strain and ordering is taken into account.