Optimization of Al-doped ZnO films for low loss plasmonic materials at telecommunication wavelengths

Al-doped ZnO (AZO) thin films were deposited on glass substrates by pulsed laser deposition for low loss plasmonic applications in the near IR (NIR). The effect of oxygen content on the electrical/optical properties of AZO films in this region was investigated. Films deposited at optimized conditions exhibit a carrier concentration of 1.2 × 1021 cm−3, carrier mobility of 18 cm2 V−1 s−1, and zero-cross-over of the real permittivity below 1.5 μm. Optical losses in these AZO films are ∼5 times smaller than conventional Ag films in the NIR. These results make AZO a promising low-loss alternative material to conventional metals for plasmonic devices operating at telecommunication wavelengths.