Fabrication and photoluminescence properties of high-quality ZnO film grown by solution-vaporizing MOCVD

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Abstract

High-quality ZnO film has been successfully grown on 2 inch c-plane sapphire substrate using Zn(DPM)2 and O2 as zinc and oxygen sources by a solution-vaporizing MOCVD technique. All films deposited at the substrate temperatures of 680 ∼ 760 °C were preferentially oriented along the (0001) direction and increasing the substrate temperature the full width at half maximum (FWHM) of the (0002) peak was decreased, as the crystallinity is improved. At the optimized substrate temperature of 740 °C the film showed the smallest FWHM was about 240 arcsec with the smoothest surface. In photoluminescence analysis of the film deposited at 740 °C, exciton emissions bound to the neutral donor (D0X) and two-electron satellites (TES) emission dominated the edge emission region while phonon replicas of D0X and TES dominated the lower energy region with a weakly donor-acceptor-pair emission. Further, a comparatively negligible defect luminescence was observed, which indicated high-quality ZnO film obtained. With increased temperature, the PL intensity of D0X and TES emissions decreased, which peaks shifts to the lower energy side, while the intensity of the free exciton emission increases and finally dominates the spectrum at room temperature. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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