1998 Volume 19 Issue 9 Pages 565-572
(GaP)n (InP)m short period superlattices (SLs) are grown on GaAs(N11), (011) and (100) substrates by gas source molecular beam epitaxy. Transmission electron microscopy and scanning tunneling spectroscopy observations show that the SLs grown on GaAs(N11)A (N=2-5) have lateral-composition-modulated dot/columnar structures with a lateral period of about 10-25 nm, while on GaAs(100) and (011), wire/vertical-superlattice structures are formed. On the other hand, the SLs on GaAs(111) show no lateral composition modulation and have quasi-perfect lateral superlattice structures. Photoluminescence (PL) peak energies are greatly dependent on substrate orientation and monolayer numbers n, m corresponding to the lateral composition modulation. Optical properties of GaP/InP SL/InGaP multilayer quantum dots (MQDs) are investigated and light emitting diodes (LEDs) are fabricated.
