Tribotronic Enhanced Photoresponsivity of a MoS₂ Phototransistor

Molybdenum disulfide (MoS₂) has attracted a great attention as an excellent 2D material for future optoelectronic devices. Here, a novel MoS₂ tribotronic phototransistor is developed by a conjunction of a MoS₂ phototransistor and a triboelectric nanogenerator (TENG) in sliding mode. When an external friction layer produces a relative sliding on the device, the induced positive charges on the back gate of the MoS₂ phototransistor act as a "gate" to increase the channel conductivity as the traditional back gate voltage does. With the sliding distance increases, the photoresponsivity of the device is drastically enhanced from 221.0 to 727.8 A W^-1 at the 100 mW cm^-2 UV excitation intensity and 1 V bias voltage. This work has extended the emerging tribotronics to the field of photodetection based on 2D material, and demonstrated a new way to realize the adjustable photoelectric devices with high photoresponsivity via human interfacing.