2D–3D heterostructure of PtS2−x /Ga2O3 and their band alignment studies for high performance and broadband photodetector

Abstract

For deep ultraviolet (UV-C) photodetectors, gallium oxide (Ga2O3) is a suitable candidate owing to its intrinsic ultra-wide band gap and high stability. However, its detection is limited within the UV-C region, which restricts it to cover a broad range, especially in visible and near-infrared (NIR) region. Therefore, constructing a heterostructure of Ga2O3 with an appropriate material having a narrow band gap is a worthwhile approach to compensate for it. In this category, PtS2 group-10 transitional metal dichalcogenide stands at the top owing to its narrow band gap (0.25–1.65 eV), high mobility, and stability for heterostructure synthesis. Moreover, heterostructure with Ga2O3 sensing in UV and PtS2 broad response in visible and IR range can broaden the spectrum from UV to NIR and to build broadband photodetector. In this work, we fabricated a 2D–3D PtS2−x /Ga2O3 heterostructure based broadband photodetector with detection from UV-C to NIR region. In addition, the PtS2−x /Ga2O3 device shows a high responsivity of 38.7 AW−1 and detectivity of 4.8 × 1013 Jones under 1100 nm light illumination at 5 V bias. A fast response of 90 ms/86 ms illustrates the device’s fast speed. An interface study between the PtS2−x and Ga2O3 was conducted using x-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy (UPS) which confirmed type-I band alignment. Finally, based on their band alignment study, a carrier transport mechanism was proposed at the interface. This work offers a new opportunity to fabricate large-area high-performance 2D–3D heterostructures based photodetectors for future optoelectronics devices.