Vinnichenko, M.M.VinnichenkoRogozin, A.A.RogozinGrambole, D.D.GramboleMunnik, F.F.MunnikKolitsch, A.A.KolitschMöller, W.W.MöllerStenzel, O.O.StenzelWilbrandt, S.S.WilbrandtChuvilin, A.A.ChuvilinKaiser, U.U.Kaiser2022-03-042022-03-042009https://publica.fraunhofer.de/handle/publica/21946410.1063/1.32127312-s2.0-69549122031This study is focused on tailoring the porosity of Nb2O5 films during reactive pulsed magnetron sputtering. Dense amorphous films containing nanopores only in deeper regions have been grown at a high rate using substrate temperatures below 60 degrees C. The films exhibit a high refractive index, n(400)=2.54, a low extinction coefficient, k(400)similar to 6x10(-4), a low mechanical stress (-90 MPa), and a negligible thermal shift. The specific depth distribution of the nanopores is believed to be the reason for the optimum trade-off between a high refractive index and low mechanical stress.enamorphous stateextinction coefficientnanoporous materialniobium compoundporosityrefractive indexsputter depositionstress effectthin film620621journal article