Photocurrent Enhancement of PtSe2 Photodetectors by Using Au Nanorods

Abstract

Compact and highly sensitive near-infrared photodetectors that are operable at room temperature are required for light detection and ranging and medical devices. Two-dimensional (2D) PtSe2, a transition metal dichalcogenide, is a candidate material for near-infrared light detection. However, the photoresponse properties of 2D PtSe2 are currently inferior to those of commercial materials. The localized surface plasmon resonance of Au has been widely used for photoelectric field enhancement and in photochemical reactions associated with phase relaxation from plasmon states that occur at specific wavelengths. Spherical Au nanocolloids exhibit an extinction peak in the visible light region, whereas nanorods can be tuned to exhibit the extinction peak in the near-infrared region by controlling their aspect ratio. In this study, hybrid Au nanorod/2D PtSe2 structure was fabricated via spin coating nanorods, with plasmon peaks in the near-infrared region, on 2D PtSe2. Furthermore, the effect of the concentration of the nanorod solution on the photoresponse of nanorod/2D PtSe2 was investigated. The photocurrent of 5 nM Au nanorod-coated 2D PtSe2 was fivefold higher than that of bare 2D PtSe2. The responsivity was maximum 908 μW/A at 0.5 V bias voltage. In addition, the photocurrent enhancement mechanism by Au nanorods is discussed.