Suppression of phase separation in (AlAs)(2 ML)(InAs)(2 ML) superlattices using Al0.48In0.52As monolayer insertions

Al0.48In0.52As monolayers (ML) are inserted at the binary-compound interfac es of (AlAs)(2 ML)(InAs)(2 ML) short-period superlattices (SPSs) during gro wth on (001) InP. The insertion of Al0.48In0.52As interlayers greater than 2 ML thick tends to suppress the phase separation that normally occurs duri ng molecular beam epitaxy of the SPS. The degree of suppression is a sensit ive function of both the monolayer-scale thickness, and the intraperiod gro wth sequence, of the interlayers in the SPS. Given this sensitivity to mono layer-scale variations in the surface-region composition, we propose that c yclical phase transition of the reconstructed surface initiates SPS decompo sition. (C) 2001 American Institute of Physics.