A comparative DFT study of the structural and electronic properties of nonpolar GaN surfaces

Enhanced radial growth of Mg doped GaN nanorods: A combined experimental and first-principles study

“…the same in bulk. Such a behavior is quite consistent with the other reports in the literature [34,35]. In case of relaxed surface of Mg doped (1010) surface, the atomic relaxation of Ga, Mg and N is bit complex.…”

Vacancy defect in bulk and at (10$\overline{1}$0) surface of GaN: A combined first-principles theoretical and experimental analysis

“…Our estimates of the band gap of bulk w -GaN is 2.06 eV at Γ point (see Fig. 1(A)) is in good agreement with earlier calculations [40,41] based on plane wave (PW) basis, but is underestimated with respect to experimental value of 3.4 eV at RT. Such underestimation of band gap is typical of DFT-LDA calculations [41][42][43][44] .…”

“…In the relaxed (1010) surface of w -GaN (shown in Fig. 5(B)), Ga atoms at the surface of the slab move inwards into the bulk, whereas N atoms move outward into the vacuum, causing a vertical separation of ≈ 0.4 Å along < 1010 > between Ga and N atoms and buckling of surface Ga-N bond by 14.2 • , which is slightly over-estimated than 7 -11 • obtained in calculations based on PW basis [41,67]. Upon structural relaxation at the surface, bond length of Ga-N at (1010) surface reduces to 1.83 Å i.e.…”

Cross-sectional shape evolution of GaN nanowires during molecular beam epitaxy growth on Si(111)

“…The equilibrium crystal shape may contain flat facets as well as continuously curved regions between them, depending on the shape of the angular plot of the surface free energy. 55 The ab initio calculations [23][24][25][26][27][28][29][30][31] Finally, based on the observation of the {1 100} facets (smeared out by the oxidation of Ga) and curved parts of the surface between them at the bottom parts of long NWs, we conclude that the polar plot of the surface free energies contains cusps in the 1 100 directions and smooth minima in the 11 20 directions.…”

“…[20][21][22] High-resolution transmission electron microscopy (TEM) confirmed this observation, but revealed that the vertices formed by adjacent 1 100 facets are not atomically abrupt, but rounded. 20 On the other hand, numerous ab initio calculations [23][24][25][26][27][28][29][30][31] have shown that the surface energies of 1 100 and 11 20 facets are close to each other, so that these two facets would be expected to be present with comparable areas in the equilibrium crystal shape.…”