Efficient and high-power AlGaN-based ultraviolet light-emitting diode grown on bulk GaN

By introducing thick bulk GaN as a substrate, we improved the performance o f an AlGaN-based ultraviolet (UV) light-emitting diode (LED). The output po wer exceeds 3 mW at the injection current of 100 mA under a bare-chip geome try. Internal quantum efficiency is estimated as more than 80%, and the pea k wavelength is 352 nm. The maximum power exceeds 10 mW at a large current injection of 400 mA, with an operation voltage of less than 6 V. These resu lts indicate that an efficient UV LED is intrinsically possible by the comb ination of appropriate device design and the nitride substrate. By introduc ing packaging technology to enhance extraction efficiency, we will have a c ompact and efficient UV light source in the wide wavelength range of 200-36 0 nm, similar to conventional longer-wavelength LEDs. (C) 2001 American Ins titute of Physics.