Ternary nitride semiconductors in the rocksalt crystal structure

Abstract

Inorganic nitrides with wurtzite crystal structures are well-known semiconductors used in optoelectronic devices. In contrast, rocksalt-based nitrides are known for their metallic and refractory properties. Breaking this dichotomy, here we report on ternary nitride semiconductors with rocksalt crystal structures, remarkable optoelectronic properties, and the general chemical formula MgxTM1-xN (TM=Ti, Zr, Hf, Nb). These compounds form over a broad metal composition range and our experiments show that Mg-rich compositions are nondegenerate semiconductors with visible-range optical absorption onsets (1.8-2.1 eV). Lattice parameters are compatible with growth on a variety of substrates, and epitaxially grown MgZrN2 exhibits remarkable electron mobilities approaching 100 cm 2 V -1 s -1 . Ab initio calculations reveal that these compounds have disorder-tunable optical properties, large dielectric constants and low carrier effective masses that are insensitive to disorder. Overall, these experimental and theoretical results highlight MgG-3TMNG-2 rocksalts as a new class of semiconductor materials with promising properties for optoelectronic applications.

Theoretical study of the phase transitions and electronic structure of (Zr0.5, Mg0.5)N and (Hf0.5, Mg0.5)N

“…Thus, our results for (Zr, Mg)N and (Hf, Mg)N solid solutions motivate additional experimental research of these compounds and comparison with theory [48,49]. In both ordered and disordered structures, the studied magnesium-based transition metal nitrides show semiconducting and thermoelectric properties.…”

Wurtzite materials in alloys of rock salt compounds

“…It is also noteworthy that the effective mass of electrons in the WZ structure (0.3m 0 at x 5 0.2) with a direct band gap is much lower than that of electrons in the RS structure (1.5m 0 at x 5 0.2) with an indirect band gap, suggesting potential optoelectronic applications of WZ alloys if they could be doped n-type. Such differences in effective masses between tetrahedrally coordinated (WZ and ZB) and octahedrally coordinated (RS and NC) polymorphs have been reported in other binary chalcogenides [8,14] and in ternary nitrides [29,30,31].…”

Zn2SbN3: growth and characterization of a metastable photoactive semiconductor

“…for Mg-based nitrides such as MgZrN2, for which mobility was improved by more than an order of magnitude using the templating effect of epitaxial substrates 30,31 . Similar epitaxial methods or alternative growth techniques can be envisioned to reduce the defect density and improve the electron mobility in Zn2SbN3.…”