Photovoltage investigations were performed on Langmuir-Blodgett (LB) corbathiene film (similar to 100 nm thick) deposited onto silicon substrate using the total current spectroscopy technique under UHV conditions. High photovoltage sensibility (of about 10(4) V W-1 cm(2)) was observed under visible-light illumination. The dependence of the photovoltage signal on both the light intensity and the wavelength was examined, and transient characteristics were measured in different spectral ranges. The nature of the observed phenomena is discussed and it is found to be the sum of photovoltage components which are generated at both interfaces : silicon/LB corbathiene film and LB corbathiene film/vacuum.