Properties of group III nitrides

Modelling of compound semiconductors: analytical bond-order potential for gallium, nitrogen and gallium nitride

“…Interestingly, the values from literature are fairly diverse. If we take the cohesive energies of N 2 as 9.91 eV/molecule and 2.81 eV/atom for the cohesive energies of solid α-Ga, then the corresponding experimental values for the cohesive energy of w-GaN are 8.96 eV/fu (Harrison 1989), 9.4 eV/fu (Edgar 1994) and 11.4 eV/fu (Jones and Rose 1984).…”

“…The melting point of GaN is not known due to experimental difficulties related to the very high temperature and N 2 pressure necessary for melting. Experiments in a high-pressure anvil cell showed that GaN does not melt at temperatures as high as 2573 K at 68 kbar (Edgar 1994).…”

“…Experimentally, the solubility of nitrogen in liquid gallium has been reported to be 1% at 1800 K and 20 kbar (Edgar 1994) and was observed to rise with pressure. The solubilities predicted by the potential (e.g., 4% at 2000 K and 200 kbar) are thus of reasonable magnitude.…”

“…Structural properties of the pure constituents like the N 2 molecule or the α-Ga structure, however, are not considered in any of the previous studies and therefore simulations of surfaces (Northrup et al 2000), defect clusters, growth or melting behaviour are not possible. In particular, studying the growth demands good elemental potentials, since the growth process involves the dissolution of molecular (Edgar 1994) or atomic N (Argoitia et al 1997) into initially pure Ga.…”

Concentration of point defects in wurtzite AlN: A hybrid functional study

“…In order to obtain consistent results, we computed µ Al(bulk) , µ N2 , µ AlN , µ O2 and µ Si(bulk) , employing the HSE functional. Similarly, we computed the formation enthalpies, ∆H f , of Al 2 O 3 and AlN, obtaining −17.91 eV and −3.55 eV, respectively, values that are on average 6% larger in modulus than the experimental ones [25,26]. Accordingly, we used in our calculations ∆H f (Si 3 N 4 ) = −5.10 eV, 6% larger in modulus than the corresponding experimental value [25].…”