Transition-Metal-Carbide (Mo2C) Multiperiod Gratings for Realization of High-Sensitivity and Broad-Spectrum Photodetection

Abstract

A novel hybrid phototransistor consisting of molybdenum carbide (Mo2C) and molybdenum disulfide (MoS2) is proposed. By exploiting the interface properties of MoS2 and Mo2C, a highly sensitive and broad-spectral response photodetector is fabricated. The underlying mechanism of the enhanced performance is the efficient hot carrier injection from Mo2C to MoS2. The strong coupling of MoS2 and Mo2C at the interface provides the significantly low Schottky barrier height (approximate to 70 meV), which gives rise to the significantly efficient hot carrier transfer from Mo2C to MoS2. The grating of metallic Mo2C produces plasmonic resonance, which provides hot carriers to the MoS2 channel. By adjusting the grating period of Mo2C (400-1000 nm), the optimal photoresponse of light can be controlled, from visible to NIR. By integrating various Mo2C multigrating periods (400-1000 nm) with MoS2, a novel photodetector is demonstrated with high responsivity (R > 10(3) A W-1) and light-to-dark current ratio (>10(2)) over a broad spectral range (405-1310 nm). The proposed novel hybrid photodetector, 2D semiconductors with multigrating 2D metallic stripes, exhibits high sensitivity and broad spectral detection of light and can overcome the inherent weakness of conventional 2D photodetectors, paving the way forward for next-generation photoelectric devices.