Transparent and conducting TiO2:Nb films made by sputter deposition:Application to spectrally selective solar reflectors

摘要

Transparent and conducting thin films of TiO2:Nb were prepared on glass and aluminum substrates bydual-target reactive DC magnetron sputtering in an Ar+O2 plasma. The Nb content lay between 0 and4.9 at as determined by ion beam analyses. X-ray diffraction showed that vacuum annealing at 450 1Cled to crystallinity and prevalence of the anatase phase. The influence of Nb doping was studied withregard to structural, optical, and electrical data. Optical constants were determined from spectrophotometricrecordings for films on glass, and the onset of free-electron behavior was documented forannealed films. The latter films, deposited onto Al2O3-coated Al, were found to display opticallyselective reflectance and to be useful for solar energy applications.