Long wavelength infrared sensor array using VO₂ microstructures fabricated on visible GaN LED

The vanadium dioxide (VO₂) microstructure arrays were integrated with In_xGaN_1-x light-emitting diodes (LEDs) to develop a long-wavelength infrared sensor array. By utilizing GaN-based LEDs as a readout unit, the VO₂/LED heterostructure directly converts temperature-induced resistance changes into visible light emission. The VO₂ layer exhibits uniform chemical configuration and atomic bonding, leading to consistent metal-to-insulator transition behavior across all pixels. The low-voltage operation was available at 2.5 V, which was readily above the turn-on voltage of the LED. The brightness of the LED and the resistivity changes of the VO₂ layer were inversely proportional, where the temperature variations can be gauged optically. Moreover, the VO₂/LED heterostructure pixels are individually addressable, which can detect directions and degrees of external heat.