Self-powered near-infrared MoS2/n-Si photodetectors with Al2O3 interface passivation

Abstract

Due to their excellent light absorption and photovoltaic effects, transition metal dichalcogenide-based heterojunctions have been widely investigated as materials for optoelectronic devices. This work presented a MoS2 film preparation process using electron beam evaporated MoO3 films as the precursor layer. The prepared MoS2 film was used in the self-powered MoS2/Al2O3/n-Si photodetector, which showed high responsivity (1.15 A W−1), normalized detectivity (1.28 × 1011 Hz1/2 cm/W) and photoresponse (τr = 28 μs) without external bias. Besides, the photodetector exhibited a large frequency-photoresponse range (up close to 100 kHz). Moreover, attributed to the excellent MoS2 quality and the effective interface passivation by ALD-deposited Al2O3, the high-speed photoresponse of the photodetector was realized. These results demonstrated the potential of applying MoS2 material prepared from electron beam evaporated MoO3 precursor layers in the high-frequency and fast photoresponse photodetectors.