Complex refractive index of InXGa1-XN thin films grown on cubic (100) GaN/MgO

• Published in: Thin solid films 2017-03, Vol.626, p.55-59
• Main Authors: Vilchis, H., Compeán-García, V.D., Orozco-Hinostroza, I.E., López-Luna, E., Vidal, M.A., Rodríguez, A.G.
• Format: Article
• Language: English
• Subjects: Ellipsometry; III-nitrides; Molecular beam epitaxy
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2017.02.016

Spectroscopic ellipsometry measurements of InXGa1-XN thin films were carried out in the photon energy range from 0.6 to 4.75eV. The samples were grown on cubic GaN/MgO (100) template substrates by plasma assisted molecular beam epitaxy. Optical properties as the energy gap, refractive index (η) and extinction coefficient (κ) were obtained from the analysis of experimental data by a parametric dielectric function model. Our results show that the behavior of the optical band gap of cubic InXGa1-XN fits Eg(x)=1.407x2−3.662x+3.2eV. The obtained bowing parameter of 1.4±0.1eV is in good agreement with reported calculated values around 1.37eV. The complex index of refraction dispersion relations η(ω) and κ(ω) are obtained for the 85–99% mostly cubic InXGa1-XN films for several In concentrations. •Cubic InXGa1-XN thin films were grown on GaN/MgO by plasma assisted MBE.•The InXGa1-XN complex refraction index from 0.6 to 4.75eV is reported.•The dispersion relations for several x are obtained by spectroscopic ellipsometry.