ABSTRACT
This chapter introduces the materials which are used as the active components of some of the most common optoelectronic devices. It shows that laser and led devices often contain several thin layers of different semiconductor alloys and every interface in such a structure is a potential site for the generation of a misfit dislocation array. The chapter focuses on the structure and the electronic properties of the semiconductor materials used in the production of efficient luminescent devices. It also introduces how simple luminescent devices operate, and the role of p-n junctions in recombination process. One method of exciting rapid recombination in a semiconductor crystal is by the introduction of a concentration of minority carriers far in excess of the equilibrium level. The chapter provides the descriptions of the semiconductors which can be used as the active materials in a number of devices not intended for use in an optical communications system.
