Electronic and optical properties of titanium-doped GaN nanowires

The electronic and optical properties of titanium (Ti) doped gallium nitride (GaN) nanowires (NWs) have been investigated using density functional theory (DFT). The donor states of near the Fermi level are mainly formed by Ti-3d orbital, and Ti-doped GaN NWs' Fermi level has an upshift compared with pure GaN NWs. The doping Ti atoms can decrease work function of GaNNWs. Moreover, the optical properties, including the complex dielectric function, optical refractive index, and absorption coefficient are discussed for radiation up to 25 eV. The results predicate that alloys exhibit a typical metallic property, in which Ti forms deep levels in the forbidden band and reduces energy gap, increases static dielectric constant and obviously red-shifts the absorption edge. The work gives a theoretical guidance for preparation of Ti-doped GaN optoelectronic nanodevices. (C) 2016 Elsevier Ltd. All rights reserved.