An Ultrahigh Responsivity (9.7 mA W −1 ) Self‐Powered Solar‐Blind Photodetector Based on Individual ZnO–Ga 2 O 3 Heterostructures

Highly crystallized ZnO–Ga 2 O 3 core–shell heterostructure microwire is synthesized by a simple one‐step chemical vapor deposition method, and constructed into a self‐powered solar‐blind (200–280 nm) photodetector with a sharp cutoff wavelength at 266 nm. The device shows an ultrahigh responsivity (9.7 mA W −1 ) at 251 nm with a high UV/visible rejection ratio ( R 251 nm / R 400 nm ) of 6.9 × 10 2 under zero bias. The self‐powered device has a fast response speed with rise time shorter than 100 µs and decay time of 900 µs, respectively. The ultrahigh responsivity, high UV/visible rejection ratio, and fast response speed make it highly suitable in practical self‐powered solar‐blind detection. Additinoally, this microstructure heterojunction design method would provide a new approach to realize the high‐performance self‐powered photodetectors.