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**Published:** Jan 1985

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**Source: **STP911-EB

The index of refraction n is calculated as a function of frequency and mole fraction x for the following compounds: Hg^{1−x}Cd^{x}Te, Al^{x}Ga^{1−x}As, and In^{1−x}Ga^{x}As^{y}P^{1−y} lattice matched to InP. Lattice matching of In^{1−x}Ga^{x}As^{y}P^{1−y} to InP requires that x = 0.466 y. The theoretical result for the refractive index is obtained from a quantum mechanical calculation of the dielectric constant of a compound semiconductor. It is given in terms of the basic material parameters of band gap energy, effective electron mass m^{n}, effective heavy hole mass m^{p}, spin orbit splitting energy, lattice constant, and carrier concentration n^{e} or p for n-type or p-type materials, respectively. If these quantities are known as functions of mole fraction x, there are no adjustable parameters involved. A negative change in the refractive index near the fundamental absorption edge is predicted on passing radiation through a crystal if the change in carrier concentration of the initially unoccupied conduction band is assumed proportional to internal intensity I. Comparison of theory with experimental data is given.

**Keywords:**

Optical constants, optical materials, refractive index, semiconductors

**Author Information:**

Jensen, B *Boston University, Boston, Mass.*

Torabi, A *Boston University, Boston, Mass.*

**Committee/Subcommittee:** F01.19

**DOI:** 10.1520/STP29008S