MICROSTRUCTURAL CHARACTERIZATION OF GAN(AS) FILMS GROWN ON (001)GAP BY MOLECULAR-BEAM EPITAXY

Samples of GaN(As)/(001)GaP grown by molecular beam epitaxy and studie d using transmission electron microscopy, have been found to exhibit i ncreasing amounts of zincblende GaN within the deposited films with in creasing As flux and independent of the N flux used. All of the sample s grown at 620 degrees C contained phases of GaAs, wurtzite GaN and zi ncblende GaN, while there was no evidence for the formation of the ter nary alloy Ga(As,N), Zincblende GaN was found to form immediately in t he presence of an As flux, while wurtzite GaN formed in the absence of As. A sample grown at 700 degrees C under the highest As flux exhibit ed single crystal zincblende GaN. Differential cross-diffusion of both N and As with P was observed, and was associated with the formation o f V-shaped pits in the substrate.