【Epitaxy Papers】Magnesium-composition engineering of p-type Ni₁₋ₓMgₓO thin films for enhanced self-powered β-Ga₂O₃ photodetection

      Researchers from Sejong University have published a dissertation titled " Magnesium-composition engineering of p-type Ni_1−xMg_xO thin films for enhanced self-powered β-Ga₂O₃ photodetection " in Applied Physics Letters.

Abstract

      Mg-composition-tuned p-type Ni_1−xMg_xO thin films were developed by radio frequency co-sputtering for solar-blind β-Ga₂O₃ heterojunction photodetectors. Mg incorporation significantly modifies the structural and optical properties of the films, inducing a transition in the preferential crystal orientation, reducing the crystallite size, and widening the optical bandgap from 3.71 to 4.23 eV. The electrical transport properties are also strongly affected, with tunable carrier concentration and mobility. The resulting heterojunction devices exhibit self-powered operation with enhanced photoresponse. The responsivity increases from 2.34 to 13.20 mA/W, and the specific detectivity reaches 4.0 × 10¹² Jones with increasing Mg content. The improved performance is attributed to the optimized structural, electrical, and band-alignment properties, together with the enhanced built-in potential at equilibrium, which promotes more efficient photogenerated carrier separation and transport. These results demonstrate the potential of Ni_1−xMg_xO as a tunable p-type material for solar-blind photodetection.

DOI：

https://doi.org/10.1063/5.0336763