Optimization of active-layer and cavity design parameters for low-threshold GaN/AlGaN double-heterostructure diode lasers

Calculations are presented aimed at optimizing the design of GaN/AlGaN double- heterostructure diode lasers emitting in the near-UV spectral region. Material parameters of GaN active medium are reviewed and specified for modeling of both edge- and surface- emitting laser devices. Comparison with published experimental results indicates that nonradiative recombination in the active region (most likely occurring at heterojunction interfaces) limits the carrier lifetime to approximately 1 ns. Theoretical minimum threshold current density is shown to depend weakly on the assumed band parameters.