Achievements and perspectives of GaN based light emitting diodes: A critical review

GaN based high brightness white LEDs have been developed as the future of lightening system. Due to their efficiency and exceptionally long lifetime they are seen as a permanent or semi-permanent lightening solution. LEDs available up to date still have many problems with their long time operation and under moderately stressed conditions. The continuous, high performing and maintenance free long operation lifetime is there to be achieved in the future. A lot of research is going on to achieve these goals. This paper provides a critical review of the state of the art LED technologies, their achievements, limitations and proposed solutions to the issues reported till date.