A Highly Polarization-sensitive Near-infrared Photodetector Based on Two-dimensional Germanane/α-CdS Heterostructure

Abstract Near-infrared (NIR) photodetectors have been widely used in imaging, remote sensing, communications, and medical fields. Emerging trends in the next-generation NIR photodetectors emphasize small-size, low-power, and high polarization-sensitivity, thus demanding novel material compositions. Based on first-principles calculations, this paper proposes the two-dimensional Germanane/α-CdS vertically stacked van der Waals heterostructure as a polarization-sensitive near-infrared photodetector with superior performance. This structure exhibits thermodynamic stability at ambient temperatures, a tunable sensitive wavelength spanning 849 nm to 2296 nm, robust photocurrent and anisotropy, and remarkable polarization sensitivity with an extinction ratio of 6.74 under a nominal bias voltage of 0.2 V.