Photodetection Properties of MoS[sub.2], WS[sub.2] and Mo[sub.x]W[sub.1-x]S[sub.2] Heterostructure: A Comparative Study

Layered transition metals dichalcogenides such as MoS[sub.2] and WS[sub.2] have shown a tunable bandgap, making them highly desirable for optoelectronic applications. Here, we report on one-step chemical vapor deposited MoS[sub.2] , WS[sub.2] and Mo[sub.x] W[sub.1-x] S[sub.2] heterostructures incorporated into photoconductive devices to be examined and compared in view of their use as potential photodetectors. Vertically aligned MoS[sub.2] nanosheets and horizontally stacked WS[sub.2] layers, and their heterostructure form Mo[sub.x] W[sub.1-x] S[sub.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[sub.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[sup.−1] and 1.4 × 10[sup.11] Jones, respectively, achieved by Mo[sub.x] W[sub.1-x] S[sub.2] . This study offers insights into the use of a facile elaboration technique for tuning the performance of Mo[sub.x] W[sub.1-x] S[sub.2] heterostructure-based photodetectors.