A high-performance planar structure metal-semiconductor-metal-type solar-blind photodetector (SBPD) was fabricated on the basis of (010)-plane β-Ga2O3 thermally oxidized from nonpolar (110)-plane GaN. A full width at half maximum of 0.486° was achieved for the X-ray rocking curve associated with (020)-plane β-Ga2O3, which is better than most reported results for the heteroepitaxially grown (-201)-plane β-Ga2O3. As a result of the relatively high crystalline quality, a dark current as low as 6.30 × 10-12 A was achieved at 5 V, while the photocurrent reached 1.86 × 10-5 A under 254 nm illumination at 600 μW/cm2. As a result, the photo-to-dark current ratio, specific detectivity, responsivity, and external quantum efficiency were calculated to be 2.95 × 106, 2.39 × 1012 Jones, 3.72 A/W, and 1815%, respectively. Moreover, the SBPD showed excellent repeatability and stability in the time-dependent photoresponse characteristics with fast relaxation time constants for the rise and decay processes of only 0.238 and 0.062 s, respectively. This study provides a promising approach to fabricate the device-level (010)-plane β-Ga2O3 film and a new way for the epitaxial growth of (010)-plane β-Ga2O3 and (110)-plane GaN as mutual substrates.
Keywords: (010)-plane β-Ga2O3; nonpolar (110)-plane GaN; solar-blind photodetector; thermal oxidization; ultrawide-bandgap semiconductor.