Boron alloying in GaN

Using first-principles calculations in the local density approximation, we studied effects of adding up to 6% boron to zinc-blende GaN. We found that the band gap increases monotonically with boron incorporation, in agreement with experiment. A composition-independent band-gap bowing parameter of 4.30 eV was determined, and proved to be large compared to bowing for other mixed cation systems. The formation enthalpy of mixing, DH, was determined for B x Ga 12x N, B x Ga 12x As, and GaAs 12x N x . A comparison of enthalpies indicates that the production of BxGa12xN films with boron concentrations of at least 5% may be possible. © 2004 American Institute of Physics. @DOI: 10.1063/1.1644910# Alloying in the group-III nitrides has diversified the properties of semiconductor materials, enabling the production of commercially important light emitting devices covering many regions of the visible spectrum. 1 Ongoing efforts to expand the range of available materials for III‐V semiconductor applications include advancing epitaxial growth techniques and engineering energy band gaps. 2‐ 4 A potential candidate for band-gap modification in the nitrides is boron. 5‐9 It has been reported that the nitride binary compound, GaN, alloyed with boron is a potential material for UV laser devices, in part since adding boron to GaN increases the band gap from the blue to the UV spectral region. 10 While prospects are positive for BxGa12xN alloys as viable III‐V semiconductor materials, single phase BxGa12xN has not been achieved for boron concentrations necessary to effect significant change in structural and electronic properties of GaN. 8 Experimental work shows that phase separation occurs for boron content in excess of 2%, a consequence of the large lattice mismatch between BN and GaN that causes internal strain during processing. 6,7,9‐15