Description:
AbstractWe present our recent results on the growth of cubic AlN (001) layers by plasma assisted molecular beam epitaxy (PAMBE) using freestanding 3C‐SiC (001) substrate. For high‐quality c‐AlN layers reflection high‐electron energy diffraction (RHEED) patterns in all azimuths show RHEED patterns of the cubic lattice, hexagonal reflections are absent. High‐resolution X‐ray diffraction (HRXRD) measurements confirm the cubic structure of the c‐AlN layers with a lattice parameter of 4.373 Å. Atomic force microscopy (AFM) scans show an atomically smooth surface with a roughness of 0.2 nm RMS. Ellipsometry studies yield the dielectric function (DF) of c‐AlN from 1 to 10 eV. The direct gap is determined with 5.93 eV at room temperature, while the indirect one is below 5.3 eV (onset of adsorption). The high‐energy part of the DF is dominated by two transitions at 7.20 and 7.95 eV attributed to critical points of the band structure.