Opto-electronic characterization of TiO₂/Metal/TiO₂ multilayers

Transparent conductive oxides (TCOs) play an important role in many optoelectronic devices such as solar cells, organic light emitting diodes, touch panel and efficiency energy applications, heat mirrors and thermoelectric materials. In recent years, many researchers proposed a TCO/metal/TCO multilayer structure with advanced electrical properties, mechanical flexibility, chemical stability and high optical transparency than a TCO single layer. Multilayer films of TiO₂/Cu/TiO₂ and TiO2/Co/TiO2were grown on glass substrate by DC magnetron sputtering technique at low temperature deposition for low cost applications. Copper interlayer was chosen as a possible replacement of Ag due to their comparable electrical conductivity and relativity low cost. Cobalt interlayer is studied for ferromagnetic properties at room temperature because of its potential applications in spintronics. The deposition time was chosen to obtain estimated thickness for layers of 30 nm while metal interlayers of 12, 15 and 18 nm thick were grown. The optical, electrical, structural and morphological properties of these films were characterized by UV-visible spectroscopy, four probe technique, X-rays diffraction patterns and atomic force microscopy (AFM) respectively. Figures of merit (FOM) are determinate for transparent solar cells electrode and others applications.Instituto de Física La Plat

Optical and Electrical Properties of TiO2/Co/TiO2 Multilayer Films Grown by DC Magnetron Sputtering

Transparent oxide multilayer films of TiO2/Co/TiO2 were grown on glass substrate by DC magnetron sputtering technique. The optical and electrical properties of these films were analyzed with the aim of substituting ITO substrate in optoelectronic devices. The samples were characterized by UV-visible spectroscopy, atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM). The effect of Co interlayer thickness (4, 8, and 12 nm) on the transmittance spectra yielded an optical absorption edge shift. The work function of these films was determined by KPFM technique allowing us to predict the Fermi level shift by extending the model for pure materials to our multilayer system. The Fermi level and optical absorption edge seem to be correlated and shifted toward lower energies when Co interlayer thickness is increased