Prospects for rare earth doped GaN lasers on Si

The recent surge of interest and research activity in Si-based lasers underscores the potential benefits that full capability in photonics could bring to the Si world. We highlight some of the recent advances in lasing based on emission from rare earth (RE) elements contained in GaN heteroepitaxially grown on Si. This approach has led to the first demonstration of visible lasing on Si. We discuss the current understanding of RE lasing sites in GaN, the intimate relationship between materials growth, optical properties and resulting laser performance. The eventual success of this approach will result in the availability of laser light sources built directly on Si substrates and operating at wavelengths throughout the visible and near-infrared (IR) range. The prospects and challenges for electrically pumped injection GaN:RE lasers, and potential applications, are discussed.