P-type non-polar m-plane ZnO films grown by plasma-assisted molecular beam epitaxy

Abstract

Non-polar ZnO thin films were grown epitaxially on m-plane sapphire substrates using plasma-assisted molecular beam epitaxy. The film is (1 0 1¯ 0) oriented ( m-plane) as identified by the X-ray diffraction pattern. The surface of ZnO film shows highly anisotropic morphology with stripes elongated along the c-axis. The nonintentionally doped non-polar ZnO film was grown under oxygen-rich condition, which exhibits weak p-type conductivity with a hole concentration of 1.3×10 16 cm −3, a Hall mobility of 0.314 cm 2 V −1 s −1, and a resistivity of 1536 Ω cm. Room-temperature photoluminescence of the p-type non-polar ZnO shows a strong UV emission at ∼3.307 eV and negligible deep level emission.