Compound Semiconductors

In addition to group IV elements, compounds of group III and group V elements, and also compounds of group II and group VI elements are often semiconductors. The common feature to all of these is that they have an average of 4 valence electrons per atom.

One example of a compound semiconductor is gallium arsenide, GaAs. In a compound semiconductor like GaAs, doping can be accomplished by slightly varying the stoichiometry, i.e., the ratio of Ga atoms to As atoms. A slight increase in the proportion of As produces n-type doping, and a slight increase in the proportion of Ga produces p-type doping.

The table below list some semiconducting elements and compounds together with their bandgaps at 300 K.

Data from R.E. Hummel, Electronic Properties of Materials, 3rd edition, Appendix 4, p. 413.