Photovoltaic effect in micrometer-thick perovskite-type oxide multilayers on Si substrates

Micrometer-thick perovskite-type multilayer heterostructures with ten thousands of unit cells, [SrNb0.05Ti0.95O3/La0.9Sr0.1MnO3](3), have been fabricated on Si substrates. The structure exhibited nonlinear and rectifying current-voltage characteristics. Stable and temporal photovoltaic effects in the multilayer have been experimentally studied by using different wavelength light sources from ultraviolet to infrared, respectively. The photovoltage and photocurrent responsivities as a function of wavelength displayed that two cutoff wavelengths occurred corresponding to the band gaps of SrNb0.05Ti0.95O3 and Si and La0.9Sr0.1MnO3. Under the pulsed laser illumination the nanosecond response characterization of the present multilayer structure was obtained. Based on the band structure of the multilayers, a possible mechanism of photovoltaic process was proposed. c 2008 American Institute of Physics. [DOI: 10.1063/1.3010373]