The demand for large, high purity, low defect, single crystal CdTe substrates with high IR transmission has accelerated because of their use in liquid phase epitaxy (LPE) of HgCdTe used in IR focal planes. CdTe is nearly lattice matched to Hgl-xCdxTe for all compositions and is chemically similar to Hgl-xCdxTe, allowing thermodynamic equilibrium between liquid and solid to be readily established at growth temperature. HgCdTe and CdTe also have a similar thermal expansion coefficients, and CdTe is optically transparent to IR radiation allowing the fabrication of backside-illuminated devices.
E. R. Gertner,
W. E. Tennant,
L. O. Bubulac,
"Developments In Large CdTe Substrate Growth", Proc. SPIE 0350, Focal Plane Methodologies III, (10 August 1983); doi: 10.1117/12.933895; https://doi.org/10.1117/12.933895