"Semiconductor materials are nominally small band gap insulators. The defining property of a semiconductor material is that it can be doped with impurities that alter its electronic properties in a controllable way."
Some materials include: Si, Ge, Sn, SiC, Te, BN, AlN, GaN, CdTe, InN, InAs, CdSe, CdS, ZnO, ZnSe, ZnS, ZnTe and numerous other materials and alloys
Wikipedia; List of Semiconductor Materials
April 4th, 2014 (http://en.wikipedia.org/wiki/List_of_semiconductor_materials)