Visible range photoresponse of vertically oriented on-chip MoS2 and WS2 thin films
MoS 2 -based ferroelectric field-effect transistor with atomic layer deposited Hf 0.5 Zr 0.5 O 2 films toward memory applications AIP Advances 10, 065107 (2020); https://doi.org/10.1063/5.0010829 Hybrid electrochemical supercapacitor based on birnessite-type MnO 2 /carbon composite as the positive electrode and carbonized iron-polyaniline/nickel graphene foam as a negative electrode AIP Advances 10, 065113 (2020); https://doi. ABSTRACT The excellent electrical properties of transition metal
... alcogenide (TMD) 2D materials promise a competitive alternative to traditional semiconductor materials for applications in optoelectronics, chemical sensing, as well as in energy harvesting and conversion. As the typical synthesis methods of TMDs produce nanoparticles, such as single or multi-layered nanoflakes, subsequent strenuous integration steps are necessary to obtain devices. Direct synthesis of the material on substrates would simplify the process and provide the means for large-scale integration and production of practical devices. In our approach, we synthesize MoS 2 and WS 2 thin films with a simple sulfurization of the respective metal films deposited by sputtering on Si/SiO 2 chips, and study their optoelectrical properties at wavelengths of 661 nm, 552 nm, and 401 nm using pulsed lasers. Both TMD thin films are found to show photoresponsivities of up to ∼5 × 10 −6 A W −1 with corresponding quantum efficiencies of ∼10 −5 , which are unexpectedly moderate, and can be attributed to their columnar microstructure, in which the basal planes of the hexagonal lattices are perpendicular to the substrate, thus, limiting the electron transport in the films parallel to the plane of the substrate.