Low-resistive and transparent AZO films prepared by PLD in magnetic field

Al2O3-doped ZnO (AZO) thin films have been deposited onto glass substrates using a split target consisting of AZO (1 wt%) and AZO (2 wt%) by pulsed laser deposition with an ArF excimer laser (λ = 193 nm, 15 mJ, 10 Hz, 0.75 J/cm2). By applying a magnetic field perpendicular to the plume, the lowest resistivity of 8.54 × 10−5Ω·cm and an average transmittance exceeding 91% over the visible range were obtained at a target-to-substrate distance of 25 mm for approximately 279-nm-thick AZO film (1.8 wt%) grown at a substrate temperature of 230 °C in vacuum. From cross-sectional TEM observations and the XRD spectrum, a reason why the low resistivity (54 × 10−5Ω·cm) was reproducibly obtained was considered to be due to the fact that a disorder of crystal growth originating in the vicinity of the interface between the substrate and the film was suppressed by application of the magnetic field and the c-axis orientation took preference, giving rise to the increase of mobility.