Overlapping effects of the optical transitions of GaNAs thin films grown by molecular beam epitaxy

摘要: Abstract Photoreflectance and ellipsometry are two very useful optical spectroscopy techniques employed to analyze the electronic band structure of semiconductors. spectra gallium arsenide nitride (GaNAs) thin films on (GaAs) layers may be composed transitions from conduction bands alloy binary (E-, E+, E0, respectively) in conjunction with their interaction spin-orbit split-off valence (E-+Δ0 E0+Δ0). For low concentration nitrogen (between 0.2 0.6 %), determination E+ becomes difficult distinguish by fact that critical points superimposed spectrum both characterization techniques. In this work, a method determine GaNAs grown GaAs molecular beam epitaxy is proposed when overlapping spectral features influences determination. When using spectroscopic techniques, modulation/excitation region depends wavelength sample characteristics, consequently thickness have been found responsible for signal overlapping. It demonstrated decreasing temperature photoreflectance process avoided, allowing correct interpretation splitting analysis discarding contribution built-in electric fields. From these results, we achieved precise experimental presence/absence predicted anti-crossing model non-destructive tools.