Optoelectronic properties of arginine-doped tungsten disulfide quantum dots synthesized via microwave heating

Abstract

Here, the hysteresis and negative photoconductivity (NPC) in arginine-doped tungsten disulfide (WS2) quantum dots (QDs) synthesized via microwave heating method were investigated and discussed. WS2 solution and arginine were used as the QDs and dopant sources, respectively. The structure of arginine-doped WS2 QDs was analyzed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The synthesized arginine-doped WS2 QDs displays a diameter of less than 10 nm and demonstrates an excitation-dependent photoluminescence (PL) behavior. The PL intensity of arginine-doped WS2 QDs displayed an 18 folds increase compared to the pristine WS2 QDs. The electrical transport demonstrated a p-type doping as a result of the introduction of arginine in WS2 QDs. I-V measurements in varying environment and laser illumination were utilized to investigate the hysteresis and negative photoconductivity (NPC) phenomena in arginine-doped WS2 QDs. Based on this analysis, the hysteresis and NPC are proposed to originate from the interaction of water and/or gas molecules adsorbed on the surface of arginine-doped WS2 QDs. This optoelectronic study of WS2 QDs is expected to contribute for the potential development and performance improvement of WS2-QD-based devices.