Abstract
The structural and electrical changes of the thin GaN layer prepared on a (001) GaAs substrate before and after rapid thermal treatment have been investigated by Raman scattering, glancing X-ray diffraction, and current–/capacitance–voltage measurements. Thin GaN layers grown on a (001) GaAs substrate by metal organic chemical vapor deposition were shown to be composed mostly of wurtzite-structured GaN (α-phase), whereas zincblende GaN (β-phase) was present near the interface between the thin GaN layer and the GaAs substrate. Rapid thermal treatment at 750–850 °C caused a structural phase of the GaN to evolve; the higher fraction of β-phase was still maintained at the hetero-interfacial region due to the strong influence of the (001) GaAs matrix. By contrast, several mixed structures of β-(111) and α-(10 1 ̄ 1) appeared near the surface of the GaN layer that was farthest from the interface region. After the thermal treatment, the electrical properties of the GaN/GaAs hetero-interface were those of a quasi-metal–insulator–semiconductor. The detailed structural changes and the related electrical characteristics of the thin GaN layer on (001) GaAs are discussed.
Published Version
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