Band alignments and polarization properties of the Zn-IV-nitrides

Abstract

Zn-IV-nitrides have a range of potential applications in electronic and optoelectronic devices and can be integrated with currently used III-nitride semiconductors and their alloys. Using hybrid density functional theory, we examine band gaps, band offsets, and polarization properties of the Zn-IV-nitrides and the ramifications of these properties on heterointerfaces formed between the Zn-IV-nitrides and III-nitrides. We find a type-II band alignment between ZnGeN₂ and GaN, where the valence band of GaN is 0.28 eV above the valence band of ZnGeN₂. Heterostructures between Zn-IV-nitrides and III-nitrides result in interface charges that allow for novel heterostructures and increased control over polarization fields. We find that an interface between In_xGa_1−xN and ZnGeN₂ can lead to zero interfacial polarization charge; however, the band alignments are unfavorable for carrier confinement in light-emitting devices. At the interface between AlN and ZnSiN₂, we predict a large two-dimensional electron gas to form, confined to the ZnSiN₂ layer.