Axial InN/InGaN Nanorod Array Heterojunction Photodetector with Ultrafast Speed

Abstract Due to wavelength‐selective characteristics, the InGaN‐based photodetectors show bright prospects in visible light communication and fast imaging system. However, the application of InGaN photodetectors with simple structures is limited in the above field owing to the slow response speed. Herein, an ultrafast photodetector based on axial InN/InGaN nanorod array (NRA) heterojunction is prepared through a self‐catalytic high (930 °C) and low (400 °C) temperature two‐step growth method by molecular beam epitaxy (MBE). The performance of photodetectors is analyzed by semiconductor device analyzer, wavelength response system (consists with a xenon lamp and monochromator), and time response system (combined by an optical chopper, a laser, and a digital oscilloscope). The photodetectors present a fast response speed with a rise/full time of 18.2/24.7 µs. Further analyses reveal a responsivity of 9.27 A W −1 and a specific detectivity of 3.54 × 10 10 Jones under −1 V bias. As a result, the axial NRA heterojunction photodetectors exhibit great potential for application in ultrafast photoelectric conversion systems and provide valuable guidance for realizing ultrafast photodetectors.