Group III-nitride lasers: a materials perspective

An overview of III-Nitride based laser diodes (LDs) is presented focusing on the materials challenges in each phase of device development. We discuss early breakthroughs leading to the first commercial GaN LDs, covering crystal growth, p-type doping, and defect reduction. Additional device issues, such as polarization effects, strain, and index dispersion are addressed as they apply to the development of blue and green LDs for pico-projector applications. State of the art device results are highlighted. Devices grown on non-polar and semi-polar GaN substrates address many polarization related problems present in c-plane GaN growth. Device results, advantages, and limitations of various non-polar and semi-polar systems are discussed in terms of polarization properties, Indium incorporation, extended defect formation, and critical thickness. A brief description of challenges and progress in UV LDs is also presented.