MODE OF GROWTH IN LP-MOVPE DEPOSITION OF GAINAS INP QUANTUM-WELLS

GalnAs/lnP multiple quantum wells of 10 periods grown by low pressure metal organic vapor phase epitaxy were studied using a careful analysis of their photoluminescence (PL) spectra and of supporting x-ray data. The results demonstrate extremely precise control of the well width. The width of well and barrier can be reproducibly adjusted by a fraction of a monolayer. This allows one to distinguish between 3-dimensional (3-D) and 2-dimensional (2-D) growth, which determines the lateral extent of the atomically smooth interfacial areas. By varying the growth time per well a discontinuous energy shift of the PL peaks is obtained for wells with widths from 1 to 8 monolayers. We show that this discontinuous energy shift corresponds to a change in well width by one monolayer. It is also observed when growth at the upper interface is carried on without interruption and a thin quaternary film is deposited at the interface. From these results the presence of atomically flat surfaces during the growth is deduced; these give a strong indication of a 2-D mode of growth for an optimized set of parameters. © 1990 The Mineral, Metal & Materials Society, Inc.