Structural and electronic properties of GaN nanowires with embedded In_xGa_1−xN nanodisks Available to Purchase

In the present study, the effects of various types of strain and indium concentration on the total energy and optoelectronic properties of GaN nanowires (NWs) with embedded In_xGa_1−xN nanodisks (NDs) are examined. In particular, the bi-axial, hydrostatic, and uniaxial strain states of the embedded In_xGa_1−xN NDs are investigated for multiple In concentrations. Density functional theory is employed to calculate the band structure of the NWs. The theoretical analysis finds that the supercell-size-dependent characteristics calculated for our 972-atom NW models are very close to the infinite supercell-size limit. It is established that the embedded In_xGa_1−xN NDs do not induce deep states in the band gap of the NWs. A bowing parameter of 1.82 eV is derived from our analysis in the quadratic Vegard's formula for the band gaps at the various In concentrations of the investigated In_xGa_1−xN NDs in GaN NW structures. It is concluded that up to ∼10% of In, the hydrostatic strain state is competitive with the bi-axial due to the radial absorption of the strain on the surfaces. Above this value, the dominant strain state is the bi-axial one. Thus, hydrostatic and bi-axial strain components coexist in the embedded NDs, and they are of different physical origin. The bi-axial strain comes from growth on lattice mismatched substrates, while the hydrostatic strain originates from the lateral relaxation of the surfaces.