The influence of a waveguiding structure on the excitonic luminescence of anatase thin films

Abstract Spectral and spatial properties of the excitonic luminescence of TiO2 (anatase) waveguide layers grown by the atomic layer deposition on dielectric and metal substrates were investigated at low temperatures. Significant changes in self-trapped-excitonic (STE) spectra were observed in the direction nearly parallel to the film surface. The characteristic broad band STE emission spectrum of anatase peaking at ∼2.3 eV was transformed into directed spectrally narrow polarised bands. It was concluded that the leaky modes of the planar waveguide were responsible for this effect.