Polarization-Sensitive Self-Powered Schottky Photodetector with High Photovoltaic Performance Induced by Geometry-Asymmetric Contacts.

Polarization-sensitive photodetectors have attracted considerable attention owing to their potential application prospects in navigation, optical switching, and communication. However, it remains challenging to develop a facile and effective strategy to simultaneously meet the demands of low power consumption, high performance, and excellent polarization sensitivity. Herein, a series of low-symmetry two-dimensional (2D) ReSe 2 Schottky photodetectors with geometry-asymmetric contacts are constructed. These devices exhibit excellent photoelectrical performance and impressive polarization sensitivity in the self-powered mode owing to the difference in the Schottky barrier height induced by the asymmetric contact areas, interfacial states, and thickness difference. Particularly, an outstanding responsivity of 379 mA/W, a decent specific detectivity of 6.8 × 10 11 Jones, and a high light on/off ratio ( I light / I dark ) of over 10 5 under 635 nm light illumination are achieved. Scanning photocurrent mapping (SPCM) measurements further confirm that the ReSe 2 /drain overlapped region (corresponding to the smaller contact area side) with a higher Schottky barrier height plays a dominant role in the generation of photocurrent. Furthermore, the proposed device displays impressive polarization ratios (PRs) of 3.1 and 3.6 at zero bias under 635 and 808 nm irradiation, respectively. The high-resolution single-pixel imaging capability is also demonstrated. This work reveals the great potential of the ReSe 2 Schottky photodetector with geometry-asymmetric contacts for high-performance, self-powered, and polarization-sensitive photodetection.