【Epitaxy Papers】Influence of substrates on the crystalline growth and UV photosensitivity of hydrogen-assisted chemical vapor deposited bi-phase Ga₂O₃ microstructures

      Researchers from the Universiti Sains Malaysia have published a dissertation titled "Influence of substrates on the crystalline growth and UV photosensitivity of hydrogen-assisted chemical vapor deposited bi-phase Ga₂O₃ microstructures" in Applied Surface Science.

Abstract

      Electrical properties of Ni/Ga₂O₃/Ni metal–semiconductor-metal (MSM) type ultraviolet photodetectors (UV PDs) are systematically studied, whereby the hydrogen reducing chemical vapor deposited Ga₂O₃ microstructures are grown on different substrates, namely Si (100), fused quartz and sapphire, which offer varied surface energies for film growth even under identical conditions. X-ray diffraction (XRD) measurement confirms the formation of mixed-phase β/α-Ga₂O₃ on Si and fused quartz substrates, and β/ε-Ga₂O₃ on sapphire substrate. Optical reflectance measurement shows optical bandgap ranging from 4.609 to 4.689 eV which is typical for Ga₂O₃. All samples demonstrate Schottky contact behaviour except for the fused quartz-based PD that manifests nearly Ohmic contact behavior, with the Ga₂O₃ PD prepared on fused quartz exhibiting the lowest dark current (0.21nA), the highest photosensitivity (1.839 × 10⁴%), the highest detectivity (7.297 × 10⁹ Jones) and the fastest rise time (0.460 s) under the UV irradiation of 254 nm at a bias voltage of 0.5 V. The superior performance over the PD fabricated on Si might correlate with the lowest strain. At the same bias voltage and under the same illumination, the PD with sapphire as template achieves a photoresponsivity of 0.750 mA/W. photosensitivity of 3.041 × 10³% and detectivity of 5.970 × 10⁹ Jones.

DOI：

https://doi.org/10.1016/j.apsusc.2026.166618