Band anticrossing in GaN x Sb 1x

Fourier transform infrared absorption measurements are presented from the dilute nitride semiconductor GaNSb with nitrogen incorporations between 0.2% and 1.0%. The divergence of transitions from the valence band to Eand E + can be seen with increasing nitrogen incorporation, consistent with theoretical predictions. The GaNSb band structure has been modeled using a five-band k ·p Hamiltonian and a band anticrossing fitting has been obtained using a nitrogen level of 0.78 eV above the valence band maximum and a coupling parameter of 2.6 eV. © 2006 American Institute of Physics. DOI: 10.1063/1.2349832 It is well documented that the anion substitution of dilute quantities of nitrogen into III-V semiconductor compounds results in a sharp decrease in the band gap of the material from that of the host compound. A number of explanations have been suggested to describe this band gap reduction, most notably the band anticrossing model BAC, calcula- tions based on empirical pseudopotential methods, and inter- pretations based on the mixing of the , L, and X character of the conduction band states. 1 The origin of this band gap reduction is the isoelectronic nature of the nitrogen atoms in the host III-V material. Though the nitrogen atom has the same electron valence as the atom it is replacing, its physical properties size, elec- tronegativity, bond length, etc. are significantly different, resulting in a considerable, highly localized perturbation to the electronic potential surrounding the atom. According to the BAC model this localized deformation in potential results in the formation of an energy level ex- tended in k space which may be resonant with the conduction band of the host. The interaction between the host conduc- tion band and resonant nitrogen level results in the formation of two nonparabolic subbands conventionally denoted E� and E+ given by the relation