Low MOCVD growth temperature controlled phase transition of Ga2O3 films for ultraviolet sensing

The influences of low growth temperatures (420-490 ?) on phase transition of Ga2O3 films grown on Al2O3 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 epsilon-phase to beta-phase in Ga2O3 films. The fluctuant Gibbs free energy change relying on growth temperature induces different growth mechanism of Ga2O3 films. Furthermore, the ultraviolet photoresponse properties of different phase compositions for Ga2O3 films are compared by constructing metal-semiconductor-metal photodetectors. It is found that mixture phase Ga2O3 films express better photodetection performance than pure phase Ga2O3 films due to the formation of built-in field within phase junction. This proposed regulation principle of Ga2O3 phase transition provides a new route to high-performance photoelectric material.

Automated summary

The influences of low growth temperatures on the phase transition of Ga2O3 films grown on Al2O3 substrates by MOCVD were investigated. The formation of a built-in field within the phase junction of mixed phase Ga2O3 films contributes to better photodetection performance compared to pure phase Ga2O3 films. This study provides a new route to high-performance photoelectric materials.