High-responsivity broadband photodetector fabricated using anodic aluminum oxide template-assisted grown β-InSe nanowires via focused ion beam deposition

Monocrystalline InSe nanowires with a [100] growth direction were prepared via vacuum hydraulic pressure injection using an anodic aluminum oxide (AAO) template at low temperature (650 °C). The lengths and diameters of the nanowires were tens of micrometers and ~100 nm, respectively. The AAO template-assisted grown β-InSe nanowires were used to fabricate a Pt-contacted single-nanowire photodetector using focused ion beam (FIB) deposition. The low dark current (several picoamperes) and ohmic contact of the Pt-contacted single-β-InSe nanowire photodetector resulted in rapid rise and fall times and high responsivity (R). The device exhibited a high R with a value of 1497 AW−1 under a 405 nm irradiation at 2 mW/cm2 and bias voltage of 1.0 V. The rapid rise and fall times of the FIB-deposited Pt-contacted single-β-InSe nanowire photodetector were 14 and 29 ms, respectively. These values are better than the respective values of 50 and 75 ms obtained using Au-contacted photodetectors fabricated via electron-beam lithography. The FIB-fabricated β-InSe nanowire device acted as a high-responsivity broadband photosensor (405–785 nm).