Modelling of semiconductor nanostructures : electronic properties and simulated optical spectra

III-V semiconductor nanostructures are widely used in optoelectronic devices (e.g. lasers and detectors) in the visible (0.4-0.8 μm), near-infrared (0.8-3 μm), mid-infrared (3-5 μm) and far-infrared (> 8 μm) wavelength ranges, with great potential for high performance and high temperature operation. As well as simple designs, complex structures incorporating low dimensional components (e.g. quantum wells and quantum dots) are not unusual. Often, the optical and electronic characteristics of these structures are altered significantly as compared to bulk material. As a prerequisite to design for different applications, the study of their electronic and optical properties is essential. With the increasing computational power of modern personal computers, computational modelling becomes viable and more efficient. Indeed, it has become routine to follow (or to precede) experimental studies with computational modelling of good interpretive and predictive power. Combined with experimental studies, this is a powerful tool to provide insight into new devices. This research work is primarily based on calculations of the electronic band structure of various semiconductor nanostructures, followed by modelling of optical transitions and optical spectra. All numerical calculations use a cost effective computational method. The applicability of the model to ultra-thin structures of short period InAs/GaSb superlattices is investigated. The work is then extended to study complex quantum-dot-in-well structures. Finally, the attempt to extract the structural parameters of quantum dots by a combination of modelling and optical spectroscopy is presented