Optical properties of GaAs1-xNx on GaAs
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
62
Journal Issue
19
Pages
13028-13033
Date Issued
2000
Author(s)
Abstract
The optical properties of GaAs1-xNx with x up to 2.5% grown by metalorganic chemical vapor deposition on GaAs(001) substrates are reported. Fundamental band gaps are obtained by photoreflectance measurements. Room-temperature pseudodielectric functions obtained by spectroscopic ellipsometry in the range from 2.7 to 5.2 eV are modeled with a three-phase structure that accounts for the GaAs1-xNx layer, native oxide, and ambient. We employ Adachi's critical-point composite model for the parametrization of GaAs1-xNx, and the compositional dependence of critical-point energies is obtained. While the energy of E0 decreases with x, those of E1 and E1+Δ1 increase with x. This fact, somewhat anomalous compared with conventional III-V alloys, indicates that the lowest-lying conduction bands along 〈111〉 directions may be perturbed by the incorporated nitrogen.
Type
journal article