Abstract
In this study, we investigate the influence of ultraviolet-ozone (UV-O-3) treatment on the photodetection properties of multilayer-MoS2 films. The MoS2 thin film photodetectors were fabricated using a sequential spin coating process at low temperature. As UV-O-3 exposure time was increased, a significant enhancement in the photodetector performance at both ultraviolet and visible-light ranges has been observed. After 5 min of exposure to UV-O-3, a 99% increase in the photoresponsivity to UV radiation, at wavelength of 320 nm, was observed under light intensity of 300 mu W cm(-2). This remarkable improvement in UV detection was accompanied by a noteworthy enhancement through the whole visible range with a maximum responsivity of 128 A/W and a highest detectivity of 1.3 x 10(12) Jones at 580 nm irradiation. On the infrared side, a drop of 13.6% in responsivity and around an order of magnitude reduction in detectivity were noticed for 750 nm irradiation after the 5 min UV-O-3 treatment. All built detectors showed reliable photo-switching properties with response time of 0.22 s. Raman spectroscopy and X-ray photoelectron spectroscopy analysis suggest that the significant improvement of optoelectronic properties is caused by the passivation of localized Sulfur vacancies by O-2 or oxygen ions that bond chemically with MoS2. Such findings provide a quick and simple route for modulating the optical properties of MoS2-based optoelectronics through a surface treatment.