Electronic and optical properties of the O-terminated AlN nanoribbons: First-principles study

We perform first-principles calculations based on density functional theory to study the electronic and optical properties of the O-terminated AlN nanoribbons (AlNNR) with both zigzag and armchair edges (ZAlNNR and AAlNNR) of different widths. The results show that ZAlNNR with six zigzag chains across the ribbon width (6-ZAlNNR) presents metallic properties and AAlNNR with sixteen dimer lines across the ribbon width (16- AAlNNR) is semimetallic because of the terminated O atoms. The dielectric function of 6- and 12-ZAlNNR or 7- and 16-AAlNNR is similar independent of the nanoribbon width if they have the same edge shape, but the wider one has a weak red shift and in the visible range (1.6-3.0 eV) the systems can be seen as optically transparent materials. The peaks of the energy loss correspond to the trailing edges in the reflection spectra.