On the band gap dependence of refractive indices of some quaternary III-V and II-VI compounds of device interest

The credibility of the model proposed by Ghosh in predicting the refractive indices of mixed semiconductor crystals of technological importance within their miscibility range as a function of band gap is demonstrated. The high-frequency refractive indices of four quaternary alloys AlxGa1-x-yInyP (y = 0.49, 0 ≤ x ≤ 0.51), InSbxAs1-x-yPy (y = 2.2x, 0 ≤ x ≤ 0.313, 0 ≤ y ≤ 0.638), CdxZn1-x-yHgySe (x + y = 1, 0.153 ≤ x ≤ 0.684, 0.316 ≤ y ≤ 0.847), and CdS1-x-ySexTey (x + y = 1, 0.15 ≤ x ≤ 0.93, 0.07 ≤ y ≤ 0.85) are calculated according to the relation n2-1 = A/(Eg + B)2 where A is an energy gap dependent constant and B is a constant depending on crystal ionicity. The calculated values show excellent agreement with the experimental data thus justifying the validity of the model