Anomalous temperature dependence of photoluminescence in GeOx films and GeOx/SiO2 nano-heterostructures

The optical properties of GeO x film and GeO x /SiO2 multilayer heterostructures (with thickness of GeO x layers down to 1 nm) were studied with the use of Raman scattering and infrared spectroscopy, ellipsometry and photoluminescence spectroscopy including temperature dependence of photoluminescence. The observed photoluminescence is related to defect (dangling bonds) in GeO x and interface defects for the case of GeO x /SiO2 multilayer heterostructures. From analysis of temperature dependence of photoluminescence intensity, it was found that rate of nonradiative transitions in GeO x film has Berthelot type, but anomalous deviations from Berthelot type temperature dependence were observed in temperature dependences of photoluminescence intensities for GeO x /SiO2 multilayer heterostructures.