Comparison of the physical properties of GaN thin films deposited on (0001) and (0112) sapphire substrates

Abstract

A direct comparison of the physical properties of GaN thin films is made as a function of the choice of substrate orientations. Gallium nitride single crystals were grown on (0001) and (011̄2) sapphire substrates by metalorganic chemical vapor deposition. Better crystallinity with fine ridgelike facets is obtained on the (011̄2) sapphire. Also lower carrier concentration and higher mobilities indicate both lower nitrogen vacancies and less oxygen incorporation on the (011̄2) sapphire. The results of this study show better physical properties of GaN thin films achieved on (011̄2) sapphire.