Photoassisted Electron–Ion Synergic Doping Induced Phase Transition of n-VO₂/p-GaN Thin-Film Heterojunction

As a typical correlated metal oxide, vanadium dioxide (VO 2 ) shows specific metal–insulator transition (MIT) properties and demonstrates great potential applications in ultrafast optoelectronic switch, resistive memory, and neuromorphic devices. Effective control of the MIT process is essential for improving the device performance. In the current study, we have first proposed a photoassisted ion-doping method to modulate the phase transition of the VO 2 layer based on the photovoltaic effect and electron–ion synergic doping in acid solution. Experimental results show that, for the prepared n-VO 2 /p-GaN nanojunction, this photoassisted strategy can effectively dope the n-VO 2 layer by H +, Al 3+, or Mg 2+ ions under light radiation and trigger consecutive insulator–metal–insulator transitions. If combined with standard lithography or electron beam etching processes, selective doping with nanoscale size area can also be achieved. This photoassisted doping method not only shows a facile route for MIT modulation via a doping route under ambient conditions but also supplies some clues for photosensitive detection in the future.