Photodetection Properties of MoS(2), WS(2) and Mo(x)W(1-x)S(2) Heterostructure: A Comparative Study

Layered transition metals dichalcogenides such as MoS(2) and WS(2) have shown a tunable bandgap, making them highly desirable for optoelectronic applications. Here, we report on one-step chemical vapor deposited MoS(2), WS(2) and Mo(x)W(1-x)S(2) heterostructures incorporated into photoconductive devices to be examined and compared in view of their use as potential photodetectors. Vertically aligned MoS(2) nanosheets and horizontally stacked WS(2) layers, and their heterostructure form Mo(x)W(1-x)S(2), exhibit direct and indirect bandgap, respectively. To analyze these structures, various characterization methods were used to elucidate their properties including Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry and high-resolution transmission electron microscopy. While all the investigated samples show a photoresponse in a broad wavelength range between 400 nm and 700 nm, the vertical MoS(2) nanosheets sample exhibits the highest performances at a low bias voltage of 5 V. Our findings demonstrate a responsivity and a specific detectivity of 47.4 mA W(−1) and 1.4 × 10(11) Jones, respectively, achieved by Mo(x)W(1-x)S(2). This study offers insights into the use of a facile elaboration technique for tuning the performance of Mo(x)W(1-x)S(2) heterostructure-based photodetectors.