Electronic structure of wurtzite and zinc-blende AlN

Abstract

The electronic structure of AlN in wurtzite and zinc-blende phases is studied experimentally and theoretically. By using x-ray emission spectroscopy, the Al 3p, Al 3s and N 2p spectral densities are obtained. The corresponding local and partial theoretical densities of states (DOS), as well as the total DOS and the band structure, are calculated by using the full potential linearized augmented plane wave method, within the framework of the density functional theory. There is a relatively good agreement between the experimental spectra and the theoretical DOS, showing a large hybridization of the valence states all along the valence band. The discrepancies between the experimental and theoretical DOS, appearing towards the high binding energies, are ascribed to an underestimation of the valence band width in the calculations. Differences between the wurtzite and zinc-blende phases are small and reflect the slight variations between the atomic arrangements of both phases. 78.70.En; 71.20.Nr; 71.15.Mb Typeset using REVT E X

The nature of electron states in AlN and α-Al2O3

“…The O 2p electrons have a band width of about 7.1 eV, larger than that (6.4 eV) of N 2p, as shown in table 1. Those results agree well with the former theoretical calculations for α-Al 2 O 3 [8,[11][12][13] and for AlN [32][33][34]. Before discussing band gaps it is important to realize that calculations based on the density-functional theory (DFT) underestimate band gaps typically by 30% for the systems considered here [35].…”

First-Principles Study of Various BN, SiC, and AlN Polytypes

“…In particular, the direct band gap is required because it is expected a higher efficiency of luminescence than the indirect band gap. From the previous studies 2,3) and the direct band gap of 2H-AlN, [20][21][22][23][24] we expect that higher AlN polytypes may have the direct band gap. Therefore, two 30H-AlN polytype structures were investigated in this study.…”

Transiciones de Fase Inducidas por Presión en los Compuestos GaN, InN y AlN / Phase Transitions Induced by Pressure in the Compounds GaN, InN and AlN

“…El AlN se caracteriza por su alto punto de fusión, alta conductividad térmica y gran módulo de volumen [19]. Presenta una brecha de energía prohibida bastante grande, 6.2 eV [20], y así, es uno de los materiales más adecuado para construir dispositivos que trabajen en la región del violeta [21]. En volumen, la forma más estable es la fase WZ.…”

“…La brecha de energía prohibida de la fase WZ es directa y la de la fase ZB es indirecta. Esto puede ser útil en la construcción de diferentes clases de puntos cuánticos o superrredes [21]. De igual forma, el GaN es un material altamente atractivo debido a su gran potencial para el desarrollo de dispositivos optoelectrónicos en el rango de longitudes de onda corta, laseres semiconductores y detectores ópticos [15,24].…”