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 x 10(4) A W-1 as well as a corresponding detectivity (D*) of 1.4 x 10(12) cm.Hz(1/2) W-1 at a light wavelength of 3.5 mu m without an applied gate voltage, similar to 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 mu m MWIR light with R of 9.6 x 10(2) A W-1 as well as a corresponding D* of similar to 8.5 x 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.