Nonpolar a-plane ZnO films fabricated on (3 0 2) γ-LiAlO 2 by pulsed laser deposition

Abstract

Nonpolar a-plane (1 1 2¯ 0) ZnO films are fabricated on (3 0 2) γ-LiAlO 2 substrate by pulsed laser deposition. When substrate temperature is low, c-plane ZnO is dominant. As growth temperature increases to ∼500 °C, pure (1 1 2¯ 0)-oriented ZnO film can be obtained. The X-ray rocking curve of a-plane ZnO film broadens sharply when growth temperature is up to ∼650 °C; such a broadening may be related to the anisotropic lateral growth rate of (1 1 2¯ 0)-oriented ZnO grains. Atomic force microscopy reveals the surface morphology changes of ZnO films deposited at different temperatures. Raman spectra reveal that a compressive stress exists in the a-plane ZnO film.