High Responsivity and EQE of Single ZnO:Sb Microwire/Ti3C2Tx Heterojunction UV Photodetector

Abstract

One-dimensional Sb-doped ZnO/Ti3C2Tx (ZnO:Sb/Ti3C2Tx) core–shell heterojunction microwires (MWs) have been fabricated in this work. The Mott–Schottky measurement confirms the p-type conductivity of the obtained ZnO:Sb MWs. The current–voltage (I–V) characteristics of the ZnO:Sb/Ti3C2Tx core–shell heterojunction show a well-defined rectification behavior with a rectification ratio of up to 1000. Photodetectors (PDs) based on a single ZnO:Sb/Ti3C2Tx core–shell heterojunction microwire exhibit a high ultraviolet (UV) response with ultrahigh responsivity (R) and an external quantum efficiency (EQE) of up to 29.2 A/W and 9920% at −1 V bias and under UV light (365 nm, 0.15 mW/cm2) irradiation. The high photocurrent of the PDs is driven by the increased Schottky barrier height of the distinct heterojunction and the extra external carrier injection. In addition, the PD exhibits satisfying self-power performance with an R of 40 mA/W and detectivity of 8.15 × 1011 Jones. This work provides a feasible reference direction for developing highly responsive microwire-based PDs.