Calculating the optical properties of multidimensional heterostructures: Application to the modeling of quaternary quantum well lasers

A method for calculating the electronic states and optical properties of multidimensional semiconductor quantum structures is described. The method is applicable to heterostructures with confinement in any number of dimensions: e.g. bulk, quantum wells, quantum wires and quantum dots. It is applied here to model bulk and multiquantum well (MQW) InGaAsP active layer quaternary lasers. The band parameters of the quaternary system required for the modeling are interpolated from the available literature. We compare bulk versus MQW performance, the effects of compressive and tensile strain, room temperature versus high temperature operation and 1.3 versus 1.55 pm wavelength operation. Our model shows that: compressive strain improves MQW laser performance. MQW lasers have higher amplification per carrier and higher differential gain than bulk lasers, however, MQW performance is far from ideal because of occupation of non-lasing minibands. This results in higher carrier densities at threshold than in bulk lasers, and may nullify the advantage of MQW lasers over bulk devices for high temperature operation.<
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