Nonlinear behaviors of valence-band splitting and deformation potential in dilute GaN xAs 1-x alloys
Journal
Journal of Applied Physics
Journal Volume
92
Journal Issue
3
Pages
1446-1449
Date Issued
2002
Author(s)
Abstract
Photoreflectance and piezoreflectance investigations have been performed on a series of GaNAs layers grown by low-pressure metal-organic chemical vapor deposition on Si-doped GaAs substrate. In addition to the observation of the fundamental band-gap and spin-orbit splitting, the valence-band splitting in thin GaN xAs 1-x epilayers strained coherently by the GaAs substrate is observed in these modulation spectra. Comparing photoreflectance with piezoreflectance spectra, we clearly establish the transitions involving the heavy-hole and light-hole bands. We find that the valence-band splitting increases with increasing nitrogen composition, and it decreases with increasing temperature. We point out that the underlying origin of our observation can be attributed to the effect of lattice mismatch between GaNAs film and GaAs substrate. We also find that the deformation potential of GaN xAs 1-x does not follow the linear interpolation of those for GaAs and GaN. It shows a strong composition dependence with a bowing in the small composition. © 2002 American Institute of Physics.
Type
journal article