High-breakdown-voltage InGaN/GaN MQW LED Achieved by Using aVaried-barrier-growth-temperature Method

Surface-texturing of sapphire by femtosecond laser pulses for photonic applications

“…In order to reveal the location of the defects we tested several post-processing treatments: wet etching in a heated (60 • C) ultrasonic bath of a buffered 10% HF aqueous solution, applied thermal shock by immersion into liquid nitrogen and by thermal annealing. For annealing we have chosen a high temperature of 1100 • C which is close to the one typically used in the growth of GaN-based blue LEDs on sapphire substrates [19][20][21]. This temperature was still smaller when compared with the temperature of surface restructuring close to the glass transition T g 2T m /3, where the melting temperature of sapphire T m = 2040 • C [22].…”