Correlation between crystallization temperature and Ge concentration in Ge-TiO2 nanocomposite thin films

The crystallization temperature and photocurrent spectrum of nanocomposite thin film with Ge nanocrystals (NCs) embedded in a TiO2 matrix are investigated. The Raman spectrum reveals that the crystallization temperature of both Ge and TiO2 increases with increases in the initial composition of the Ge, which is controlled by employing different Ge-chip numbers set on a sputtering target of TiO2. The photocurrent spectrum indicates a peak at a wavelength of 410 nm due to crystallization of TiO2 with a rutile structure during post-annealing.