Refractive index of a native oxide anodically grown on GaAs

Abstract

The refractive index of an anodically grown oxide on GaAs has been measured throughout the visible and near infrared and the data fitted to a single oscillator Sellmeier equation. Accurate refractive-index data is required for possible use of anodic oxides as antireflection coatings on GaAs electro-optic devices. For 11 as-grown oxides the measured refractive index for λ=632.8 nm was n=1.7786±0.0138, while for five annealed oxides (259 °C for 1 h in N2) n=1.7469±0.0095. The calculated refractive index of annealed oxides at the emission wavelengths of interest for GaAs-AlGaAs fiber communication sources is n=1.724±0.006 at λ=890±20 nm.