Estimation of Junction Temperature in Single 228 nm-Band AlGaN Far-Ultraviolet-C Light-Emitting Diode on c-Sapphire Having 1.8 mW Power and 0.32% External Quantum Efficiency

Abstract

The increasing resistance of methicillin-resistant Staphylococcusaureus to antibiotics is a major challenge faced by mankind in thehistory of medical science and according to United Nations, 700-000 patients worldwide die every year from an infection with multidrug-resistant organisms (MROs). Aluminum gallium nitride-based 228 nm Far-ultraviolet-C (Far-UVC) lightsources can be safely used as a germicidal application in both manned as wellas in unmanned environments against these MROs. Previously, the 228 nm Far-UVC light-emitting diode (LED) with emission power of 1 mW was reported by ourgroup, however, the value of external quantum efficiency (EQE) was not reportedusing conventional thick Ni (20 nm)/Au (100 nm) p-electrode. Herein, animproved Far-UVC LED on c-Sapphire is attempted using a special technique in SR4000 type of metal-organic chemical vapor deposition reactor to control the Al composition in n-AlGaN buffer and across the 2 inch-wafer. As a result, the light emission power of 1.8 mW and EQE of 0.32% in 228 nm Far-UVC LED aresuccessfully achieved using very thin p-electrode (Ni/Au). However, arelatively high junction temperature of ≈100°C around thejunction of Far-UVC LED is observed. Finally, some simple heat-sink modules forheat dissipation of Far-UVC LED panel with light power of 30 mW are implemented.