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 × 10⁴ A W^-1 as well as a corresponding detectivity ( D*) of 1.4 × 10¹² 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 × 10² A W^-1 as well as a corresponding D* of ∼8.5 × 10¹⁰ 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.