Low MOCVD growth temperature controlled phase transition of Ga2O3 films for ultraviolet sensing. (September 2022)

• Record Type: Journal Article
• Authors: Yue, Jianying; Ji, Xueqiang; Qi, Xiaohui; Li, Shan; Yan, Zuyong; Liu, Zeng; Li, Peigang; Wu, Zhenping; Guo, Yufeng; Tang, Weihua
• Is Part Of: Vacuum. Volume 203(2022)
• Publication Date: 2022-09
• Subjects: Ga2O3 -- Growth temperature -- Phase transition -- MOCVD -- Photodetector; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2022.111270
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: The influences of low growth temperatures (420–490 °C) on phase transition of Ga2 O3 films grown on Al2 O3 substrates by means of metal-organic chemical vapor deposition (MOCVD) are investigated here. The changes of crystal structure, phase composition, surface and cross-sectional morphologies are carried out by X-ray diffraction, atomic force microscope and field-emission scanning electron microscope to reveal the detail evolution from ε -phase to β -phase in Ga2 O3 films. The fluctuant Gibbs free energy change relying on growth temperature induces different growth mechanism of Ga2 O3 films. Furthermore, the ultraviolet photoresponse properties of different phase compositions for Ga2 O3 films are compared by constructing metal-semiconductor-metal photodetectors. It is found that mixture phase Ga2 O3 films express better photodetection performance than pure phase Ga2 O3 films due to the formation of built-in field within phase junction. This proposed regulation principle of Ga2 O3 phase transition provides a new route to high-performance photoelectric material. Highlights: Phase transition from ε -Ga2 O3 to β -Ga2 O3 was captured in a low growth temperature window of 420–490 °C by MOCVD. Different Ga2 O3 phase compositions resulted in varying crystal structures, surface morphologies and UV sensing properties. Ga2 O3 films with mixture phases demonstrated better photoresponse due to the formation of built-in field within phase junction.