Non Equilibrium Current Activated Pressure Assisted Densification (CAPAD) Processing of Aluminum Nitride Doped with Rare Earths for Laser Applications

Doctor of Philosophy, Graduate Program in Mechanical Engineering
University of California, Riverside, March 2015
Dr. Javier Garay, Chairperson

The  performance  of  Solid  State  lasers  and  solid  state  lighting  have  long suffered from thermal management difficulties. Thermal management continues to be one of the major challenges in the development of high powered light sources such as solid state lasers. In particular, the low thermal conductivity of standard photoluminescent (PL) host materials limits the overall power output and/or duty cycle. Overheating in laser host materials can lead to performance issues  and  ultimately  irreparable  failure.  One  significant  problem  is  the materials ability to tolerate thermal shock and the stresses caused by thermal gradients. A material with high thermal conductivity will be able to dissipate more  heat  while  maintaining  a  smaller  thermal  gradient,  thus  reducing  the degradation of performance from thermal effects such as thermal lensing and thermally  induced  fracture. Aluminum  Nitride’s  wide  band  gap  and  high thermal conductivity offer the potential to improve some of these problems. In this dissertation the author presents research conducted on the processing and doping  of  Aluminum  Nitride  for  photoluminescent  and  solid  state  laser applications. Areas discussed include, non equilibrium CAPAD processing of doped and undoped AlN, doping of AlN for visible and infrared emission and thermomechanical properties of doped AlN.