Enhanced Photobolometric Effect in an All-Semimetal van der Waals Heterostructure

The utilization of the photobolometric effect in emerging van der Waals (vdWs) semimetallic materials shows promise for ultrabroadband photodetection, ranging from visible to terahertz frequencies. However, individual two-dimensional (2D) semimetals face a significant challenge due to their inherently high dark current and low temperature coefficient of conductance (TCC), which limits device performance. To address this issue, this study introduces an approach by creating a heterostructure using 2D semimetallic transition metal dichacolgenides (TMDs), specifically TiS₂ and WTe₂. Through standard transport and photocurrent measurements, the TiS₂-WTe₂ heterostructure demonstrates an improved photobolometric effect in the junction area at low temperatures, which can be adjusted by modifying the length of the photosensitive channel. The generated photocurrent in different areas of the device exhibits varying temperature dependencies, and the photoresponse remains detectable up to room temperature with a commendable signal-to-noise ratio. These findings offer valuable insights into the design and advancement of thin-film optoelectronic devices, with the aim of achieving exceptional performance and unique functionality.