High power violet laser diodes with crack‐free layers on GaN substrates

Nitride based violet laser diodes grown on GaN substrates have been investigated. A grooved substrate, having a striped pattern with a pitch of 400 μm, has been prepared and epitaxial growth has been performed. No cracks have been observed in the epi-layers. The violet laser device has been fabricated and characterised. At a pulsed output power of 210 mW, the operating current and the voltage have been 164 mA and 6.6 V, respectively. The mean-time-to-failure has been estimated to be over 3000 h under pulsed condition with an output power of 210 mW at 80 °C.