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Title: Effects of rapid thermal annealing on properties of Ga-doped Mg{sub x}Zn{sub 1−x}O films and Ga-doped Mg{sub x}Zn{sub 1−x}O/AlGaN heterojunction diodes

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/1.4892591· OSTI ID:22314590
 [1];  [1]
  1. Department of Electronics Engineering, Vanung University, Chung-Li 32061, Taiwan (China)

This study investigated the thermal annealing effects of Ga-doped Mg{sub x}Zn{sub 1−x}O (GMZO) films and GMZO/AlGaN heterojunction diodes. GMZO films were deposited using a radio-frequency magnetron sputtering system with a 4-in. ZnO/MgO/Ga{sub 2}O{sub 3} target. In addition, the Hall results, X-ray diffraction, transparent performance, and X-ray photoelectron spectroscopy (XPS) spectra were measured. The as-grown GMZO film deposited in this study exhibited a high transparency with transmittances over 95% in the visible region (360–700 nm) and a sharp absorption edge in the UV region (275–350 nm). The phenomenon of phase separation in the GMZO films was investigated based on the XPS spectra, revealing that an increase in the O-Zn signal accompanied a decline in the O-Ga signal after the thermal annealing. Moreover, the current-voltage (I-V) characteristics of the GMZO/AlGaN n-p junction diodes were examined at different annealing temperatures. The light emission derived from the forward-biased junction and near-ultraviolet (near-UV) light emission was evident at all p-n junctions. The n-GMZO/p-AlGaN diode annealed at 800 °C exhibited a brighter near-UV emission compared with the other diodes. In addition, the spectrum of diode annealed at 800 °C exhibited a broad peak at 474 nm (2.62 eV) and a tail of the emission spectrum extending to 850 nm. Based on these findings, the GMZO films are suitable for forming transparent contact layers in optoelectronic devices, and the n-GMZO/p-AlGaN junction diode is a feasible alternative in near-UV light emission devices.

OSTI ID:
22314590
Journal Information:
Journal of Applied Physics, Vol. 116, Issue 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
Country of Publication:
United States
Language:
English