Bandgap Energy of GaNAs Alloys Grown on (001) GaAs by Metalorganic Molecular Beam Epitaxy

Autor: Katsuhiro Uesugi, Katsuhiro Uesugi, Ikuo Suemune, Ikuo Suemune
Zdroj: Japanese Journal of Applied Physics; December 1997, Vol. 36 Issue: 12 pL1572-L1572, 1p
Abstrakt: GaNAs layers have been successfully grown on GaAs(001) substrates by metalorganic molecular beam epitaxy using monomethylhydrazine (MMHy) as a N source. The N composition in GaNAs increased with decreasing growth temperature and with the increasing MMHy precursor ratio in the group-V precursors. We obtained a N composition of 7.2% in GaNAs. With the increased N composition, the absorption spectra shifted to lower energy and the absorption coefficient increased by one order of magnitude. When the N composition in GaNAs is less than 1%, the measured bandgap energy is very close to the theoretical bandgap energy based on the dielectric model. However, for N composition larger than 1%, the bandgap energy deviated considerably from the dielectric model, and approached the theoretical bandgap energy based on the first-principles supercell models.
Databáze: Supplemental Index