CONTROL AND CHARACTERIZATION OF ORDERING IN GAINP

Ga0.51In0.49P layers have been grown by organometallic vapor phase epi taxy on GaAs substrates with [110]-oriented grooves on the surface tha t have an important effect on the formation of Cu-Pt ordered structure s during growth. In this work, the groove shape is demonstrated to be critically important. For the optimum groove shape, single domains of the (111BAR) and (111BAR) variants of the Cu-Pt ordered structure are formed''on the two sides of the groove. Shallow grooves produce large domains on each side of the groove containing small domains of the oth er variant. For deep grooves, only a single variant is formed on each side of the groove, but the domains are small. For substrates with dee p grooves on a GaAs substrate misoriented by 9-degrees, every groove c ontains large regions of highly ordered and completely disordered mate rial separated by a few micrometers. This allows a direct determinatio n of the effect of ordering on the band gap of the material using cath odoluminescence spectroscopy, allowing the first direct demonstration that ordering reduces the energy band gap of a III/V alloy.