It is well known that UV-C light peaking at around 265 nm has highest disinfection efficiency against both bacteria and virus, because this wavelength range corresponds to the absorption peak of DNA/RNA. However, it becomes difficult to obtain high output power from AlGaN-based LEDs as the wavelength becomes shorter, especially below 270nm, because dislocations contained in the AlGaN layer decrease the internal quantum efficiency. Yingfenghas overcome this technical issue by using high quality AlN single crystal substrates fabricated by HexaTech. The AlN substrate allows us to grow AlGaN layers with very low dislocation density of about 104 cm-2, which is less than 1/1000 in AlGaN layer grown on sapphire substrate usually used for fabricating UV-C LEDs. In addition, our AlN substrate has superior UV transparency which suppress the absorption of UV light in the AlN substrates. This unique LED structure bring over 50mW output power of 265 nm LEDs. In-company sterilization test revealed that germicidal effectiveness against SARS-CoV-2 of 265 nm is 1.8 times higher than of 280nm and actual germicidal power of 265 nm LEDs is approximately 1.3 times higher than that of 280 nm LEDs. We hope that high germicidal power of 265 nm LED brings customer’s benefit such as improved throughput and design flexibility of disinfection devices.