Photoelectric properties of large area WTe2 thin films prepared by pulsed laser deposition

WTe2 is considered as an exceptionally desirable material for broadband photodetection. However, the controllable preparation of WTe2 with large area and high quality has become a key factor limiting its photoelectric detection. In this paper, large-area, favorable crystal quality WTe2 thin film were prepared with the size of 10 x 10 mm by pulsed laser deposition in conjunction with post-annealing on a SiO2 substrate. X-ray diffraction and Raman spectrum confirmed the crystallization quality of WTe2 which referred to an orthorhombic structure. The atomic ratio of W and Te, as characterized by EDS, is approximately 1:2. The large-area WTe2 thin film, post-annealed at 400 degrees C, demonstrates relatively strong optoelectronic performance with a responsivity of 1.4 mA/W and a specific detectivity of 2.3 x 106 Jones. This study provide a new strategy for the large-scale preparation of WTe2 thin films by combining pulsed laser deposition and post annealing.