REFRACTIVE-INDEXES OF ZINCBLENDE STRUCTURE BETA-GAN(001) IN THE SUBBAND-GAP REGION (0.7-3.3 EV)

Refractive indices n and absorption coefficients ct of epitaxial metas table zincblende structure beta GaN(001) were determined over the subb and-gap energy range between 0.8-3.1 eV from an analysis of optical tr ansmission spectra. n was found to vary from 2.25 to 0.8 eV (1.55 mu m ) to 2.50 at 3.1 eV (0.4 mu m) with an energy E (eV) dependence that i s well described by a Sellmeir-type dispersion relationship, n(2)(E)=1 +148/(38.3- E(2)). The refractive indices of beta-GaN are 3%-4% smalle r than previously reported values for hexagonal alpha-GaN. (C) 1996 Am erican Institute of Physics.