Metal–Semiconductor–Metal Photodetectors Based on β-MgGaO Thin Films

Abstract

Ultrawide-bandgap (UWBG) deep-ultraviolet photodetectors have received great attention due to their versatile applications in the fields of scientific research, civilian infrastructure, military defense, etc. In this perspective, we fabricated deep-ultraviolet β-MgGaO metal–semiconductor–metal photodetectors with interdigital Pt/Au metal contacts. β-Phase MgGaO ternary alloy thin films of different Mg atomic percentages were grown using oxygen plasma-assisted molecular beam epitaxy. Ultrawide bandgaps of 5.03, 5.09, 5.15, and 5.22 eV were achieved for thin films with and without Mg2+ incorporation, and light transmittances of all samples were around 90% in the visible region. Raman spectra indicate that Mg2+ atoms have replaced the position of Ga3+ ions in both octahedral and tetrahedral chains. The responsivity of the detectors was investigated. The irradiation wavelength-, temperature-, and power-dependent I–V curves, photocurrent spectra, and dynamics of the photocurrents were measured. This work suggests that UWBG β-MgGaO semiconductors have a potential for deep-ultraviolet photodetectors and other photonic device applications.