Highly Sensitive InSb Nanosheets Infrared Photodetector Passivated by Ferroelectric Polymer

Indium antimony is a direct, narrow bandgap III–V semiconductor with ultrahigh carrier mobility and an attractive optoelectronic device candidate for use in the visible to infrared region. Here, an infrared (IR) photodetector based on high-quality InSb nanosheets (NSs) is presented, which shows a clear photoresponse over a broad spectral range from visible (637 nm) to infrared (4.3 µm). Due to the high surface-to-volume ratio of nanostructured materials, defects on the sample surface can affect performance, which is a disadvantage for the ambipolar InSb photodetectors. To eliminate the impact of sample surface defects on performance, the surface of the sample is passivated with a ferroelectric film and the mechanism of increased sensitivity is explored. After covering the protective layer, the performance of the detector is greatly improved. The responsivity and detectivity of the photodetector are 311.5 AW⁻¹ and 9.8 × 10⁹ Jones, respectively. Compared with devices before passivation, the dark current is two orders of magnitude lower, the responsivity is 20 times higher, and the photoresponse time is shortened from seconds to the order of milliseconds. These InSb NSs with their outstanding photoelectric properties have great potential for developing next-generation nanoscale optoelectronic devices.