395 nm GaN-based near-ultraviolet light-emitting diodes on Si substrates with a high wall-plug efficiency of 520%@350 mA

The high-performance 395 nm GaN-based near-ultraviolet (UV) light emitting diodes (LEDs) on Si substrates have been obtained by designing an AlN buffer layer to decrease the dislocations density of the GaN layer. By adopting a multi-layer structure with a high- and low-V/III ratio alternation, a high-quality AlN buffer layer has been obtained with a small full-width at half-maximum (FWHM) for AlN(0002) X-ray rocking curve (XRC) of 648 arcsec and a small root-mean-square roughness of 0.11 nm. By applying the optimized AlN buffer layer, the high-quality GaN layer with GaN(0002) and GaN(10-12) XRC FWHM of 260 and 270 arcsec have been obtained, and the high-performance GaN-based near-UV LED wafers and chips have been fabricated accordingly. The as-fabricated near-UV LED chips exhibit a light output power of 550 mW with a forward voltage of 3.02 V at 350 mA, corresponding to a wall-plug efficiency of 52.0%. These chips with outstanding performance are of paramount importance in the application of curing, sterilization, efficient white lighting, etc.