LAUSR

The development of MoS2 with 2D/3D heterostructures can provide a significant breakthrough for the enhancement of photodetection abilities such as an increase in light absorption and expanding detection ranges. To date, although the synthesis of MoS2 layer with 3D nanostructures using a chemical vapor deposition (CVD) process has been successfully demonstrated, most studies have concentrated on electrochemical applications that utilize structural strengths, for example, a large specific surface area and electrochemically active sites. Here, for the first time, we report spectral light absorption induced by the plasmon resonances in single-layer MoS2 with vertically aligned nanoflakes grown by a CVD process. Treatment with oxygen plasma results in the formation of a sub-stoichiometric phase of MoOx in the vertical nanoflakes, which exhibits a high electron density of 4.5 × 1013 cm-2. The sub-stoichiometric MoOx with a high electron doping level, that is locally present on the single-layer MoS2 surface, induces an absorption band in the near-infrared (NIR) wavelength ranges of 1000 - 1750 nm due to the plasmon resonances. Finally, we demonstrate the enhancement of photo-detection ability for broadening the detection range from the visible region to the NIR region in oxygen-treated single-layer MoS2 with vertically aligned nanoflakes.