Band gap widening of MBE grown InN layers by impurity incorporation

Band gap widening due to impurity contamination such as oxygen (O) incorporation into InN layers has been observed by growth without PBN sealing in the RF-plasma reactor. Furthermore, V/III ratio dependence of the absorption edge of InN layers grown under O-contaminated background has shown a strong correlation with that of the residual carrier concentration. A clearly red-shift of the absorption edge has been also observed for InN layers grown under the simultaneous irradiation of Ga beam. These results strongly indicate that O may be one of the strong candidates of impurity identified as an origin of band gap widening of InN.