Monte Carlo simulations of capture into quantum well structures

Abstract

The purpose of this paper is to simulate capture events into quantum well structures of the kinds studied in luminescence experiments in order to understand the carrier dynamics, to extract local electron and hole capture times and to relate microscopic carrier processes to the luminescence signal. To do this, a quantum mechanical model for charge capture by a quantum well has been incorporated into a self-consistent Monte Carlo simulation of carrier transport in quantum well laser diodes. The capture model makes use of the established technique of modifying Fermi's golden rule to calculate a dimensionless capture probability instead of a capture rate. This model has been used to simulate time-resolved photoluminescence experiments on a variety of InGaAsP-based structures which have unstrained quantum wells. Local electron and hole capture times have been extracted from the transport data for simulations performed at 300 K, and these times oscillate as a function of well width. Wells 85-90 Å wide permit fast electron capture into a second electronic subband (0.56 ps capture time) and hole capture into a second light hole band (0.44 ps). This may be contrasted with a 75 Å well for which electron capture into the single conduction subband exceeds 1.7 ps, and the peak hole capture time is 1.1 ps.