NUMERICAL DRIFT-DIFFUSION SIMULATION OF AUGER HOT-ELECTRON TRANSPORT IN INGAASP INP DOUBLE-HETEROJUNCTION LASER-DIODES

This paper considers the adaptation of drift-diffusion device simulati on methodology to study Auger-recombination-induced hot electron trans port characteristics in InGaAsP/InP double heterostructure laser diode s. In order to model the transport behaviour of the Auger hot electron s, we decompose the conventional electron current continuity equation into two components, with one for the Auger hot electrons and the othe r for the low-energy electrons. These equations, which use the energy relaxation time parameter to model the dynamics of the Auger hot elect rons, are then coupled with the hole current continuity equation and t he Poisson equation to obtain self-consistent solutions. Results from the case studies of one-dimensional N-p-P InGaAsP/InP double heterojun ction laser diodes with material composition corresponding to 1.3 mum and 1.55 mum wavelength emissions are presented. We have observed that hot electrons generated through Auger recombination inside the active region can spread into both the N- and the P-InP cladding layers. Wit hin the drift-diffusion framework, it is demonstrated that the hot ele ctron concentration in the N-InP cladding layer can be five orders of magnitude higher than that in the P-InP cladding layer. Because energy transport of the hot electrons is not modelled under the drift-diffus ion approximation, the simulated results are discussed to highlight so me of the possible limitations in using drift-diffusion physics to stu dy Auger hot electron transport behaviour. The importance of taking en ergy transport into account is emphasized.