Plasmon–Microcavity Coupling and Fabry–Pèrot Lasing in a ZnO:Ga Microwire/p-Type Gallium Nitride Heterojunction

In recent years, electroluminescent devices of ZnO have been the focus of attention and research. In this paper, we fabricated a ZnO:Ga microwire/p-type gallium nitride heterojunction light-emitting diode and found a lasing emission near the silver electrode. We interpret this lasing as trap-state FP-mode lasing because a series of small peaks appear in the spectrum and the positions of three lasing peaks are close to the emission peak from the trap state. After sputtering gold on the surface of the ZnO:Ga microwire, the luminescence of the device was enhanced and anomalous spectral signals appeared at a reverse current of 20 mA. The luminescence enhancement is due to the hot electron transfer induced by plasmons, and the strange spectral phenomenon was attributed to the Fano resonance caused by plasmon–microcavity coupling. The above research can provide some guidance for the design of LEDs and laser devices.