Band gap energy determination of TiO2 nanorod array by Kubelka - Munk method and investigation of the UV photodetection of Au/TiO2/Au

This paper studies the structural, optical and ultraviolet photodetection of rutile titanium dioxide nanorods (TiO2). A regular array of relatively vertically aligned TiO2 nanorods has been grown on fluorine doped tin oxide (FTO) coated glass substrate by using one step hydrothermal synthesis method. The morphology and crystal structure were studied by scanning electron microscopy and X- ray diffraction, respectively. Photoluminescence (PL) and diffuse reflectance spectroscopy were used as experimental methods for band gap energy estimation of nanostructures. The room temperature Photoluminescence spectra were measured under two different excitation energies of 4.13 and 3.82 eV. The results indicate the dependence of the PL spectrum to excitation energy. Thus, the band gap energy of nanorods is approximately equal to 3.04 eV and observed in the PL spectrum under 4.13 eV excitation energy. Comparing the applied reported methods for calculating the band gap energy by using diffuse reflectance spectra and Kubelka- Munk method shows that the most relevance to PL data exist with application of  equation. The ultraviolet photodetection performance of TiO2 nanorods in  Au/TiO2/Au device structure under 365 nm illumination is evaluated by determining resposivity, sensivity and rise and decay tims.