MXene-based metal halide perovskite vertical field-effect transistors: Toward high current-density and high photodetection performance

Metal halide perovskite field-effect transistors (MHP-FETs) are of great interest due to the fascinating photonic and electronic properties of perovskite semiconductors, and their low-temperature solution processability. However, present MHP-FETs suffer from the low current-density problem due to the low device mobility, which is an obstacle to their applications. Herein, we tackle this problem by adopting the vertical field-effect transistor (VFET) structure for the fabrication of MHP-VFETs. We show MHP-VFETs can be achieved by employing the MXene (Ti3C2Tx) film as perforated source electrodes, which are essential elements in VFETs, via a simple solution process. The MHP-VFETs exhibit high on/off ratio of 105 and, moreover, show large current density of over 6 mA cm−2, thanks to the ultrashort channel length of the VFETs. Furthermore, the devices are found to exhibit excellent photodetection performance with photoresponsivity of 2.1 × 103 A W−1 and detectivity of 7.84 × 1015 Jones. This study not only provides a route to achieve high-performance MHP-FETs but also shows the very promising prospects of MHP-VFETs for applications as backplane thin-film transistors and high-performance phototransistors.