Physical simulation of optoelectronic semiconductor devices

The operation of optoelectronic semiconductor devices couple electrical, optical, and thermal effects that are difficult to analyze. Simulation tools help device designers determine how these various effects interact. This thesis describes the SimWindows optoelectronic device simulator. The author of this thesis developed SimWindows as the first simulator to combine the major physical models necessary for simulating optoelectronic devices such as surface emitting lasers and quantum well solar cells. The software extends many of the traditional electrical models by adding effects such as quantum confinement, tunneling current, and complete Fermi-Dirac statistics. The optical model includes computing electromagnetic field reflections at interfaces and determining the resonant frequency of laser cavities. SimWindows implements two thermal models which either compute the lattice temperature or the electron temperature. This combination of models can predict many aspects of optoelectronic devices that traditional simulation programs can not. SimWindows provides a large degree of flexibility for the user to control and modify the models in SimWindows. The user can also add new models depending on the circumstances.; This thesis will present results for two examples: a vertical cavity surface emitting laser (VCSEL) and a multi-quantum well solar cell. SimWindows results will focus on the two Bragg reflectors of the VCSEL and evaluate designs to improve the reflectors. Simulation results will analyze how the improved reflectors affect the overall characteristics of the VCSEL. The main result from this VCSEL analysis will be that despite similarities between the two Bragg reflectors, their design must be independent to achieve the best VCSEL design.; For the multi-quantum well solar cell, SimWindows results will focus on the impact of hot electrons on the characteristics of the solar cell. Results will show that hot electrons can reduce unwanted recombination in the quantum well absorption regions, but also yield an undesirable backward diffusion of hot electrons. The main result will be that the relative size of these two effects determines the short circuit current and open circuit voltage of the solar cell.