Appl. Phys. Express 4, 102103 (2011)

Efficient electrically driven green semiconductor lasers are in strong demand for applications such as full-colour laser projectors and displays. Attention has been particularly focused on GaN-based devices grown on c-plane substrates, which have so far provided the highest wall-plug efficiencies. Scientists from US firm Corning have now shown that a GaN laser grown on a semipolar plane substrate is an attractive alternative that provides continuous-wave output powers of up to 60 mW at 10 °C and 35 mW at 60 °C for a drive current of 350 mA, without any signs of roll off. This study also demonstrates that semipolar devices offer the benefits of a reasonable injection efficiency and a temperature-independent slope efficiency. In addition, this device does not seem to require the electron blocking layer often employed in c-plane devices. The disadvantage, however, is that the reported emission wavelength range of Corning's latest devices is 508–522nm — still slightly lower than that ideally needed for display applications, which desire a wavelength as close to 535 nm as possible.