Ultrasensitive Mid-wavelength Infrared Photodetection Based on a Single InAs Nanowire

One-dimensional InAs nanowire (NW)-based photodetectors have been widely studied due to their potential application in mid-wavelength infrared (MWIR) photon detection. However, the limited performance and complicated photoresponse mechanism of InAs NW-based photodetectors have held back their true potential for real application. In this study, we developed ferroelectric polymer P(VDF-TrFE)-coated InAs NW-based photodetectors and demonstrated that the electrostatic field caused by polarized ferroelectric materials modifies the surface electron–hole distribution as well as the band structure of InAs NWs, resulting in ultrasensitive photoresponse and a wide photodetection spectral range. Our single InAs NW photodetectors exhibit a high responsivity ( R ) of 1.6 × 10 4 A W –1 as well as a corresponding detectivity ( D *) of 1.4 × 10 12 cm·Hz 1/2 W –1 at a light wavelength of 3.5 μm without an applied gate voltage, ∼3–4 orders higher than the maximum value of photoresponsivity reported or commercially used MWIR photodetectors. Moreover, our device shows below band gap photoresponse for 4.3 μm MWIR light with R of 9.6 × 10 2 A W –1 as well as a corresponding D * of ∼8.5 × 10 10 cm·Hz 1/2 W –1 at 77 K. Our study shows that this approach is promising for fabrication of high-performance NW-based photodetectors for MWIR photon detection.