Physical and Optical Characterization of GaN Doped with Neodymium grown by Plasma-Assisted Molecular Beam Epixaty

Solid state laser applications using crystals doped with Nd have been quite successful and/or very promising (e.g., Nd:YAG). What these crystals lack is the ability to dissipate thermal energy, with thermal conductivities on the order of 5-15 W/m-K, which limits their high power operation. By changing the matrix to a wide bandgap semiconductor such as GaN (or AlGaN), with a thermal conductivity of 100-300 W/m-K, the improvement in heat extraction could allow for major gains in solid state laser technology. It has been shown previously that rare-earth (RE) dopants such as Er, Pr, Tm, and Eu are well-suited to III-nitride semiconductors [1-4]. Although there have been difficulties in preserving optical quality while achieving adequate concentrations, light emission from RE-doped GaN has been demonstrated by photoluminescence (PL), electroluminescence (EL), and cathodoluminescence (CL). Two techniques exist for the introduction of RE-dopants into the semiconductor matrix: ion implantation and in situ doping during growth. Ion implantation imparts damage to the matrix that can not be removed by annealing, and it creates a doping profile due to the depth limitations for implanting RE species. Kim and Holloway report the EL properties of GaN doped with Nd by in situ reactive sputtering.