jats:pWe report a high efficiency single Ag nanowire (NW)/p-GaN substrate Schottky junction-based ultraviolet light emitting diode (UV-LED). The device demonstrates deep UV free exciton electroluminescence at 362.5 nm. The dominant emission, detectable at ultralow (&lt;1 μA) forward current, does not exhibit any shifts when the forward current is increased. External quantum efficiency (EQE) as high as 0.9% is achieved at 25 μA current at room temperature. Experiments and simulation analysis show that devices fabricated with thinner Ag NWs have higher EQE. However, for very thin Ag NWs (diameter &lt; 250 nm), this trend breaks down due to heat accumulation in the NWs. Our simple device architecture offers a potentially cost-effective scheme to fabricate high efficiency Schottky junction-based UV-LEDs.</jats:p>