Enhanced Photobolometric\nEffect in an All-Semimetal\nvan der Waals Heterostructure

The utilization of the photobolometric effect in emerging\nvan der\nWaals (vdWs) semimetallic materials shows promise for ultrabroadband\nphotodetection, ranging from visible to terahertz frequencies. However,\nindividual two-dimensional (2D) semimetals face a significant challenge\ndue to their inherently high dark current and low temperature coefficient\nof conductance (TCC), which limits device performance. To address\nthis issue, this study introduces an approach by creating a heterostructure\nusing 2D semimetallic transition metal dichacolgenides (TMDs), specifically\nTiS<sub>2</sub> and WTe<sub>2</sub>. Through standard transport and\nphotocurrent measurements, the TiS<sub>2</sub>–WTe<sub>2</sub> heterostructure demonstrates an improved photobolometric effect\nin the junction area at low temperatures, which can be adjusted by\nmodifying the length of the photosensitive channel. The generated\nphotocurrent in different areas of the device exhibits varying temperature\ndependencies, and the photoresponse remains detectable up to room\ntemperature with a commendable signal-to-noise ratio. These findings\noffer valuable insights into the design and advancement of thin-film\noptoelectronic devices, with the aim of achieving exceptional performance\nand unique functionality.