Utilizing the Ability of Few-Layer MoS₂ Integrated with MOCVD-Grown ZnGa₂O₄ for Thermally Stable Deep Ultraviolet Detection Performance

A thermally robust deep ultraviolet photodetector (DUV PD) was developed by utilizing the complementary characteristics of few-layer (FL)-MoS2 as a van der Waals heterostructure on top of the MOCVD-grown zinc gallate. Using a low-cost technique, a type I straddling heterointerface is formed by selectively scratching the FL-MoS2 with a razor blade on the zinc gallate substrate. Not only does this creative method provide outstanding stability across a broad temperature range, but it also provides exceptional sensitivity to DUV light between 200 and 280 nm. The detectivity of the device is 4.9 × 1018 Jones under a 10 V bias, and a fast response of 77 ms is realized. The device can significantly detect extremely low levels of noise, having a noise equivalent power (NEP) of 1.2 × 10–20 A/Hz1/2. The band alignment in FL-MoS2/ZnGa2O4 unveils a valence band offset of 1.75 eV and a compelling conduction band offset of 1.65 eV. The performance of the photodetector in DUV is far better than that of Si APD available in the market (APD130A2(/M) from Thorlabs Inc.), with a detectivity of ∼1013 Jones, a responsivity ∼2 A/W, and NEP 2.1 × 10–13 A/Hz1/2. The excellent performance of this FL-MoS2/ZnGa2O4/FL-MoS2 makes it highly compatible with practical applications of DUV photodetectors under elevated-temperature environments.