Ellipsometric study of the optical properties of InGaAsN layers

We report the optical properties of the quaternary compound semiconductor, InxGa1-xAs1-yNy, with various indium and nitrogen contents. The refractive indices of InxGa1-xAs1-yNy epilayers were systematically studied by variabl e angle spectroscopic ellipsometry (VASE) in the wavelength range of 400 to 700 nm. Analysis of the spectroscopic ellipsometry data indicated that the refractive index of InxGa1-xAs1-yNy increases in proportion to the indium and nitrogen contents. It is also found that the rate of increase of the re fractive index in In(x)Ga(1-x)AS(1-y)N(y) with increasing nitrogen content is much larger than that with increasing indium content. The transition ene rgy El as a function of N composition for In(0.3)Gn(0.7)AS(1-y)N(y) epilaye rs was also examined based on the second-derivative spectra of the dielectr ic function.