Bulk Transport Properties of Main Semiconductors

Abstract

The number of semiconductor materials that are today studied and employed by the electronic industry is very large and continuously increasing, in particular after the introduction of semiconductor heterostructures. For space reasons, however, in this textbook we will limit ourselves to the two most “popular” materials, namely silicon and gallium arsenide. Hopefully, the analysis of the transport properties of these two examples will enable the reader to understand the main electronic transport properties of most materials. Silicon is by far the most used material in semiconductor industry, both because of its large availability and because of the existence of a “natural oxide”, very suitable for the realization of electronic devices. Gallium arsenide, on the contrary, is much more convenient for optoelectronic applications, owing to its direct energy gap, appropriate for a transformation between electronic and optical energies. Furthermore, its small electron effective mass (0.067 compared to an average 0.295 in Si) provides a higher electron mobility.