Space‐Confined Chemical Vapor Deposition Synthesis of Ultrathin HfS₂ Flakes for Optoelectronic Application

Abstract

Abstract Due to the predicted excellent electronic properties superior to group VIB (Mo and W) transition metal dichalcogenides (TMDs), group IVB TMDs have enormous potential in nanoelectronics. Here, the synthesis of ultrathin HfS 2 flakes via space‐confined chemical vapor deposition, realized by an inner quartz tube, is demonstrated. Moreover, the effect of key growth parameters including the dimensions of confined space and deposition temperature on the growth behavior of products is systematically studied. Typical as‐synthesized HfS 2 is a hexagonal‐like flake with a smallest thickness of ≈1.2 nm (bilayer) and an edge size of ≈5 µm. The photodetector based on as‐synthesized HfS 2 flakes demonstrates excellent optoelectronic performance with a fast photoresponse time (55 ms), which is attributed to the high‐quality crystal structure obtained at a high deposition temperature and the ultraclean interface between HfS 2 and the mica substrate. With such properties HfS 2 holds great potential for optoelectronics applications.