Enhanced Photocurrent Performance of Flexible Micro‐Photodetector Based on PN Nanowires Heterojunction using All‐Laser Direct Patterning

Abstract UV micro‐photodetectors (mPDs) have received significant attention owing to the increasing demand for application in wearable healthcare devices. However, mPDs often suffer from tiny signals owing to their small size. Although this problem can be overcome by using low‐dimensional nanomaterials with high surface‐to‐volume ratios, such as nanowires (NWs), selective synthesis of functional NWs on the desired position of the specific substrate is challenging. This study introduces, for the first time, the laser‐induced hydrothermal growth (LIHG) process, in which a strongly focused laser beam generates a localized high‐temperature field, enabling the localized growth of CuO NWs on the desired position of the specific substrate. Also, an all‐laser direct patterning process for the fabrication of a flexible mPD based on a p‐CuO NW/n‐ZnO NW heterojunction is demonstrated. The PN NWs heterojunction exhibits remarkable photocurrent enhancement compared to a homojunction with a single semiconductor material. Furthermore, the all‐laser direct patterning process of the flexible PN NWs heterojunction can be applied for the fabrication of other flexible optoelectronic applications.