Resumo

NUNEZ-GONZALEZ, Roberto; REYES-SERRATO, Armando; POSADA-AMARILLAS, Alvaro  e  GALVAN, Donald H. First-principles calculation of the band gap of Al_xGa_1-xN and In_xGa_1-x N. Rev. mex. fis. [online]. 2008, vol.54, suppl.2, pp.111-118. ISSN 0035-001X.

Ab-initio calculations of the band gap variation of Al_xGa_1-xN and In_xGa_1-x N ternary compounds were carried out using the Full-Potential Linearized Augmented Plane Waves (FLAPW) method, within the Density Functional Theory (DFT). These nitrides were modeled in their wurtzite structure using the supercell method, for concentrations x = 0, 0.25, 0.50, 0.75 and 1.0. To optimize the cell parameters of the binary compounds we used the PBE96 (Perdew et al., Phys. Rev. Lett. 77 (1996) 3865) exchange-correlation functional. For the band structure calculations, we used both PBE96 and EV93 (Engel et al., Phys. Rev. B 47 (1993) 13164) exchange-correlation functionals. We considered experimental and calculated (with PBE96) lattice parameters to work out the electronic properties. We found that the fundamental gap is direct in all compounds. The calculation with EV93 functional gives a better band gap estimation for binary nitrides. The bowing parameter was also estimated obtaining the values b = 0.74 eV for Al_xGa_1-xN and b = 2.12 eV for In_xGa_1-x N.

Palavras-chave : Ab-initio calculations; band structure; bowing parameter; FLAPW; nitrides.

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