Selective Direct Growth of Atomic Layered HfS2 on Hexagonal Boron Nitride for High Performance Photodetectors

Hafnium disulfide (HfS2) has attracted significant interest because of the predicted excellent electronic properties superior to group VIB transition metal dichalcogenides. On the other hand, atomically thin hexagonal boron nitride (h-BN) is an ideal dielectric substrate for optoelectronic applications of other 2D materials. Here, for the first time, we report the direct growth of high-quality atomic layered HfS(2)on few-layer h-BN transferred on SiO2/Si substrates by chemical vapor deposition. It was found that the HfS(2)layers are selectively grown on h-BN rather than on SiO2/Si. Density functional theory calculations are performed to help understand the mechanism of selective growth of HfS2. Furthermore, the photodetectors based on the HfS2/h-BN heterostructures exhibit excellent visible-light sensing performance, such as a high on/off ratio of more than 10(5), an ultrafast response rate of about 200 mu s, a high responsivity of 26.5 mA W-1, and a competitive detectivity exceeding 3 x 10(11)Jones, superior to the vast majority of the reported 2D materials based photodetectors. The remarkable performance of the HfS2/h-BN photodetector is attributed to the unique features of 2D h-BN substrate.