Ultraviolet–Visible Photodetector Driven by Local Electrostatic Field from Chargeable Electret

Abstract

Metal oxide semiconductors have been developed for ultraviolet–visible photodetectors, but improving sensitivity has remained a challenge due to poor mobility and carrier losses. In this study, a high‐performance photodetector is achieved by implementing a chargeable electret to regulate carrier transmission properties in the CuBi2O4 (CBO) conductive channel. As expected, the positively charged device shows improved performance, with a broadband detection range covering 250–600 nm, maximum responsivity and detectivity of around 10.65 A W−1 and 8.56 × 1012 Jones, and a fast rise and decay time of 50 and 300 µs, respectively. Mechanism analyses suggest two roles of the electret layer: 1) positive charges in the electret layer attract electrons and leave a pure hole conductive channel with less carrier recombination and trapping; 2) holes in the conductive channel move in one direction with less carrier collision and scattering. This work has demonstrated an effective strategy for providing a durable and stable ultra‐high electrostatic field to improve the sensitivity of photodetectors.

Contact-Electro-Catalysis Through Electret Behavior to Facilitate Electron Transfer

“…The desired result is that space charges can provide an internal electrostatic field to the external environment, enabling the subsequent CEC reaction under an electric field (Figure 1d). 16,17,21,22 3.2. Physicochemical Characterization of PTFE Dielectric Powder.…”

“…These charges were captured by various deep wells or defects in the PTFE lattice and thus stored inside PTFE to form a space-charge layer at a certain depth on the PTFE surface (Figure c). The desired result is that space charges can provide an internal electrostatic field to the external environment, enabling the subsequent CEC reaction under an electric field (Figure d). ,,, …”