Structural and electronic properties of wurtzite Bx Al1-x N from first-principles calculations
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
King Abdullah University of Science and Technology (KAUST); Advanced Semiconductor Laboratory; Thuwal 23955-6900 Saudi Arabia
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AbstractThe structural and electronic properties of wurtzite BAlN (0≤x≤1) are studied using density functional theory. The change of lattice parameters with increased B composition shows small bowing parameters and thus slightly nonlinearity. The bandgap exhibits strong dependence on the B composition, where transition from direct to indirect bandgap occurs at a relatively low B composition (x∼0.12) is observed, above which the bandgap of BAlN maintained indirect, thus desirable for low-absorption optical structures. The Γ-A and Γ-K indirect bandgaps are dominant at lower and higher B compositions, respectively. Density of states (DOS) of the valence band is susceptible to the B incorporation. Strong hybridization of Al, B, and N in p-states leads to high DOS near the valence band maximum. The hybridization of Al and B in s-states at lower B compositions and p-states of B at higher B compositions give rise to high DOS near lower end of the upper valence band. Charge density analysis reveals the B-N chemical bond is more covalent than the Al-N bond. This will lead to more covalent crystal with increasing B composition. Dramatic change of the heavy hole effective mass is found due to significant curvature increase of the band by minor B incorporation.
CitationZhang M, Li X (2017) Structural and electronic properties of wurtzite B x Al1-x N from first-principles calculations. physica status solidi (b) 254: 1600749. Available: http://dx.doi.org/10.1002/pssb.201600749.
SponsorsThe authors would like to acknowledge the support of Gulf Cooperation Council (GCC) Research Program REP/1/3189-01-01, KAUST Baseline BAS/1/1664-01-01, and KAUST Equipment Fund BAS/1/1664-01-07.
Journalphysica status solidi (b)