Dielectric function and refractive index of GaBix As1-x (x = 0.035, 0.052, 0.075)

MBE grown GaBiAs epitaxial layers with Bi content of 3.5%, 5.2%, and 7.5%, sandwiched between GaAs, have been investigated by spectroscopic ellipsometry in the infrared and absorption threshold spectral regions. The real and imaginary parts of the dielectric function of GaBiAs indicate bandgap Eg and spin‐orbit splitting Δ0+ values close to literature data. The refractive index of GaBiAs in the IR region 0.2–0.8 eV exceeds that of GaAs by ca. 0.8%, 2.3%, and 3.6%, for Bi content 3.5 %, 5.2%, and 7.5%, respectively (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)