IV–VI Semiconductors

Abstract

The IV–VI semiconductors are among the most interesting materials in solid state physics. Many are found in the rock-salt structure, and structural transitions are common. The most widely studied compounds in this group are PbTe, PbSe, PbS, SnTe, and GeTe. Their lattice constants are given in Table 11.1. These materials have small gaps which are usually less than 0.5 eV, hence they are good candidates for devices like infrared lasers and detectors. Despite their simple crystal structure, some of these compounds exhibit ferroelectric, paraelectric, and superconducting behavior. In addition, the temperature dependence of the energy gaps, the energy positions of impurity levels, the high doping levels found, the static dielectric constants, and the electronic structure of some of the alloys of these compounds appear to be anomalous compared to the “conventional behavior” of the diamond and zinc-blende semiconductors.