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

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 MoS 2 film preparation process using electron beam evaporated MoO 3 films as the precursor layer. The prepared MoS 2 film was used in the self-powered MoS 2 /Al 2 O 3 /n-Si photodetector, which showed high responsivity (1.15 A W−1), normalized detectivity (1.28 × 1011 Hz1/2 cm/W) and photoresponse (τ r = 28 μs) without external bias. Besides, the photodetector exhibited a large frequency-photoresponse range (up close to 100 kHz). Moreover, attributed to the excellent MoS 2 quality and the effective interface passivation by ALD-deposited Al 2 O 3 , the high-speed photoresponse of the photodetector was realized. These results demonstrated the potential of applying MoS 2 material prepared from electron beam evaporated MoO 3 precursor layers in the high-frequency and fast photoresponse photodetectors. • MoS 2 films were prepared by e-beam evaporation of MoO 3 films as precursor layers. • ALD-deposited Al 2 O 3 insertion layers were used to enhance device performance. • MoS 2 /Al 2 O 3 /n-Si PDs were made on Si substrate with an inverted pyramid structure. • The produced PDs showed a self-driven R of 1.15 A/W and a D* of 1.28 × 1011 Jones. • MoS 2 -based PDs depicted excellent stability for high pulses of light at 100 kHz. [ABSTRACT FROM AUTHOR]