Multimechanism Synergistic Photodetectors with Ultrabroad Spectrum Response from 375 nm to 10 µm

Abstract

Broadening the spectral range of photodetectors is an essential topic in photonics. Traditional photodetectors are widely used; however, the realization of ultrabroad spectrum photodetectors remains a challenge. Here, a photodetector constructed by a hybrid quasi-freestanding structure of organic ferroelectric poly(vinylidene fluoride–trifluoroethylene) (P(VDF-TrFE)) with molybdenum disulfide (MoS2) is demonstrated. The 2D MoS2 with the ultrathin structure brings a great benefit of heat dissipation for the pyroelectric infrared detector. By coupling the mechanisms of pyroelectrics, photoconductor, and phototransistor effect, an ultrabroad spectrum response ranging from ultraviolet (375 nm) to long-wavelength infrared (10 µm) is achieved. In the 2.76–10 µm spectral range, the 2D MoS2 is used to read and amplify the photocurrent induced by the pyroelectric effect of P(VDF-TrFE). The sensitivity of the device in this spectral range is greatly enhanced. A high responsivity of 140 mA W−1, an on/off photocurrent switching ratio up to 103, and a quick response of 5.5 ms are achieved. Moreover, the ferroelectric polarization field dramatically enhances the photoconductive properties of MoS2 and restrains dark current and noise. This approach constitutes a reliable route toward realizing high-performance photodetectors with a remarkable ultrabroad spectrum response, high responsivity, low power consumption, and room-temperature operation.