GaAsN Alloys and GaN/GaAs Double-Hetero Structures

Abstract

ABSTRACTTernary alloys; GaAsN (N<3%) were grown by plasma-assisted metalorganic chemical vapor deposition using triethylgallium, AsH3, and plasma-cracked NH3 or N2 as the precursors. More N atoms were incorporated into the alloys from N2 than NH3 at constant N/As ratios. Both photoluminescence peaks and optical absorption edges were redshifted from GaAs bandgap with increasing the N content, indicating the GaAsN alloys have narrower bandgaps than GaAs.GaN/GaAs double-hetero structures were grown by exposing GaAs surfaces to N-radical flux to replace surface As atoms by N atoms, and by growing GaAs on the thin GaN layers. When the GaN thickness exceeded one-monolayer, the GaN/GaAs interfaces and the GaAs cap layers deteriorated drastically. The one-monolayer-thick GaN embedded in GaAs attracts electrons and shows intense photoluminescence, whereas the GaN cluster is non-radiative, probably because of the defects caused by the large lattice-mismatch between GaN and GaAs.