Gate-Tunable Photovoltaic Effect in MoTe2 Lateral Homojunction

Since it is urgent to develop flexibly tunable photosensors in artificial vision network, atomically thin 2D materials are promising candidates for susceptible gate modulation and thickness-dependent bandgaps. Here, a gate-tunable MoTe2 lateral homojunction is reported with asymmetric thickness. Through gate modulation, a tunable and abrupt built-in field can form at the interface and realize the broadband self-driven photodetection ranging from visible (405 nm) to near-wavelength infrared (1550 nm) region. The photocarriers are effectively separated by the tunable electric-field, leading to an obvious photovoltaic behavior with maximum V-oc of 0.27 V (0.20 V) and maximum PCE of 6% (1.85%) under light illumination of 635 nm (1064 nm). It also demonstrates an ultra-low noise power density at the positive gate voltage, revealing a hypersensitized photodetection with a maximum photoresponsivity of 1200 mA W-1 (560 mA W-1) and specific detectivity up to 10(12) (10(11)) Jones under 635 nm (1064 nm). Meanwhile, the underlying mechanism of the gate control effect on the electrical, optoelectrical properties and noise level is revealed. By utilizing the tunable photovoltages as logic optoelectronic application, the lateral homojunction can convert a light signal to different electric signals. This photovoltage-tunable homojunction hosts promising innovation for potential development of computational sensors and logic optoelectronics.

Automated summary

This study presents a novel gate-tunable lateral homojunction of MoTe2, which enables broad-spectrum photodetection and conversion of light signals to electrical signals through gate modulation. The structure exhibits excellent optoelectronic properties, offering a new pathway for potential development in computational sensors and logic optoelectronics.