2D-3D heterostructure of PtS 2- x /Ga 2 O 3 and their band alignment studies for high performance and broadband photodetector.

For deep ultraviolet (UV-C) photodetectors, gallium oxide (Ga 2 O 3 ) 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 Ga 2 O 3 with an appropriate material having a narrow band gap is a worthwhile approach to compensate for it. In this category, PtS 2 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 Ga 2 O 3 sensing in UV and PtS 2 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 PtS 2- x /Ga 2 O 3 heterostructure based broadband photodetector with detection from UV-C to NIR region. In addition, the PtS 2- x /Ga 2 O 3 device shows a high responsivity of 38.7 AW -1 and detectivity of 4.8 × 10 13 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 PtS 2- x and Ga 2 O 3 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.