ZNGEP2 GAP MULTIPLE HETEROSTRUCTURES ON GAP SUBSTRATES/

In this paper we report on ZnGeP2/GaP double and multiple heterostruct ures grown by or,organometallic chemical vapor deposition at 580 degre es C, using dimethylzinc, trimethylgallium, germane and phosphine as s ource gases. With appropriate growth conditions, mirror smooth epitaxi al ZnGeP2/GaP multiple heterostructures are obtained on (001) GaP subs trates. Cross-sectional SEM and TEM and SIMS studies show that the int erfaces of these heterostructures are sharp and smooth. Etching studie s of the top GaP (001) surface of GaP/ZnGeP2/GaP double heterostructur es reveal a dislocation density of similar to 5 x 10(4) cm(-2). Select ed area (110) electron diffraction patterns show that the GaP layers c rystallize in the zincblende structure and the ZnGeP2 layers crystalli ze in the chalcopyrite structure. This is the first time that multiple heterostructures combining these two crystal structures have been mad e.