Fabrication of a WS₂/p-Si Heterostructure Photocathode Using Direct Hybrid Thermolysis

P–N heterostructures based on transition-metal dichelcongenides (TMDs) and a conventional semiconductor, such as p-Si, have been considered a promising structure for next-generation electronic devices and applications. However, synthesis of high-quality, wafer-scale TMDs, particularly WS2 on p-Si, is challenging. Herein, we propose an efficient method to directly grow WS2 crystals on p-Si via a hybrid thermolysis process. The WO3 is deposited to prepare the p-Si surface for coating of the (NH4)2WS4 precursor and converted to WS2/p-Si during thermolysis. Moreover, the WS2/p-Si heterojunction photocathode is fabricated and used in solar hydrogen production. The fabricated n-WS2/p-Si heterojunction provided an onset potential of +0.022 V at 10 mA/cm2 and a benchmark current density of −9.8 ± 1.2 mA/cm2 at 0 V. This method reliably and efficiently produced high-quality, wafer-scale WS2 crystals and overcame the challenges associated with previous approaches. The approach developed in this research demonstrates a magnificent progress in the fabrication of 2D material-based electronic devices.