compound semiconductor
Compound semiconductors differ from elementary semiconductors in that they consist of two or more chemical compounds of different chemical elements. They are designated according to the main groups of the periodic table whose chemical elements are combined.
If chemical elements of a main group, for example group III, are combined with semiconductors of main group V, then the new compound semiconductor is called a III-V compound semiconductor. By combining a semiconductor such as germanium or silicon with another chemical element, a compound semiconductor with different properties is created.
The most commonly used chemical elements are those in main groups III, IV and V. The chemical elements in main group III, the earth metals and boron group, include boron (B), aluminum (Al), gallium ( Ga) and indium( In). Group IV includes carbon (C), silicon( Si), germanium( Ge), and tin (Sn); nitrogen-phosphorus group V includes nitrogen (N), phosphorus (P), arsenic ( As), and antimony (Sb); and group VI includes sulfur (S), selenium ( Se), and tellurium (Te). Most compound semiconductors are made from these main groups. They are therefore called III-V compound semiconductors or IV-IV compound sem iconductors and are characterized by special properties compared to the elemental semiconductors.
For example, the compound semiconductor gallium arsenide( GaAs) belongs to the group of III-V compound semiconductors and silicon germanium( SiGe) to the IV-IV compound semiconductors.
In addition to the groups mentioned, there are II-VI compound sem iconductors and I-VII compound semiconductors. The chemical elements in subgroup II include zinc (Zn), cadmium ( Cd), and mercury (Hg), and those in group VI include sulfur (S), selenium (Se), and tellurium (Te). The II-VI compound derivatives are cadmium selenide (CdSe) and cadmium telluride( CdTe).