Abstract
In this chapter we consider the important optical and electronic processes which influence the properties of semiconductor photonic devices. Focussing on a number of material systems, we describe semiconductor materials and structures used for light-emitting applications (lasers and LEDs) operating in a wide spectral range from visible to mid-infrared. The main carrier recombination mechanisms in semiconductor devices are discussed and experimental methodologies for measuring and analysing these mechanisms are introduced. Near infra-red (IR) quantum well (QW) lasers are discussed in depth considering several new approaches to overcome fundamental performance issues. Different approaches for the longer wavelength (mid-IR) semiconductor devices are reviewed showing the benefits of different approaches to material and device design where energy efficiency and high temperature operation are the principal concerns. Finally, semiconductor lasers and LEDs for the visible spectral range are briefly introduced in terms of the most important issues related to their performance.