Tunable photo-response in the visible to NIR spectrum range of Germanium-based junctionless nanowire transistor.

In this paper, the phototransistor behavior is investigated in the germanium-on-insulator (GeOI)-based junctionless nanowire (JL-NW) transistor under various light conditions. High responsivity and photosensitivity are attributed in the fully depleted regime within the visible and near-infrared bands. The impact of light is also investigated in detail on the electronic and transfer characteristics such as energy bandgap, carrier distribution, electrostatic potential, electric field, generation and recombination rates. Further, the channel doping and thickness are tuned to optimize the optical responsivity. The significant tunability of responsivity is observed with increasing channel thickness. The device exhibits fast optical switching performance, which is further enhanced at higher input light power. Overall, at the nanoscale dimension, our proposed phototransistor demonstrates better detectivity with a significantly smaller illumination area. Thus, the GeOI-based JL-NW phototransistors can be used for imaging (visible wavelength range) and bioimaging (near-infrared wavelength range) applications in advanced technology nodes.