A polar-dependent phase with spontaneous atomic ordering is found in a nonpolar (112̄0) plane In0.08Ga0.92N film grown by metalorganic vapor-phase epitaxy. An atomic arrangement is a periodic sequence of group-III sublattices, such as In0.04Ga0.96N/In 0.12Ga0.88N, that is only observed in a nitrogen polar region through systematic transmission electron microscopy investigation. Cathodoluminescence (CL) in the nitrogen polar region, i.e., spontaneously ordered atomic structure of InGaN, reveals anomalous emission behavior, specifically an S-shape-like (increase-decrease) temperature dependence of CL peak energy. It is suggested that the spontaneous ordered atomic structure of InGaN plays the role of a localized center owing to band gap shrinkage, which has been reported in other III-V alloy systems.
- Phase ordering
ASJC Scopus subject areas
- General Engineering
- General Physics and Astronomy