【Epitaxy Papers】Improving the Photodetector Performance of β-Ga₂O₃ Thin Film by Mg Diffusion

      Researchers from the Shenyang National Laboratory for Materials Science have published a dissertation titled "Improving the Photodetector Performance of β-Ga₂O₃ Thin Film by Mg Diffusion" in ACS Applied Electronic Materials.

Abstract

      Gallium oxide (Ga₂O₃) is a solar-blind photodetector material widely used in people’s daily lives and the field of national defense due to its wide and direct band gap, excellent chemical stability, and good thermal conductivity. However, vacancies of Ga and lattice O atoms in the film significantly degrade device performance. Here, high-quality β-Ga₂O₃ thin films were grown on MgO and Al₂O₃ substrates by pulsed laser deposition (PLD) method. The microstructure and chemical composition were characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was found that Mg in the MgO substrate diffuses into the β-Ga₂O₃ thin film, while atoms in the Al₂O₃ substrate do not diffuse. The diffused Mg will suppress the loss of O, which can increase the proportion of lattice O. Photodetector performance measurements reveal that due to the diffusion of Mg, the β-Ga₂O₃ photodetector grown on MgO substrate has higher photocurrent (6.03 × 10^–5 A) and detectivity (1.2 × 10¹³ Jones) at a response wavelength of 254 nm. Importantly, the responsivity and external quantum efficiency (EQE) of the heteroepitaxial β-Ga₂O₃/MgO film-based photodetector are as high as 7.94 A/W and 3900% which are more than 25 times higher than the photodetector based on the β-Ga₂O₃/Al₂O₃ and are one of the best values of β-Ga₂O₃ based photodetectors at present. Our findings shed light on applying high-performance solar-blind photodetectors and related optoelectronic devices.

DOI：

https://doi.org/10.1021/acsaelm.5c02383