Influence of Electrochemical Hydrogenation on the Circular Photocurrent in the Ag/Pd Nanocomposite

This work reports on a circular photocurrent in Ag/Pd nanocomposite films. The films, containing metal (Ag-Pd) and semiconductor (PdO) nanocrystallites in amorphous lead-silicate glass, are modified by electrochemical hydrogenation in a sulfuric acid solution. The photocurrent in the modified nanocomposite films is excited by nanosecond laser pulses at wavelengths of 532, 1064, and 1550 nm. In order to determine the circular and linear contributions in a transverse photocurrent, the dependences of the photocurrent on the degree of circular polarization of the exciting radiation are investigated. It is found that the electrochemical hydrogenation modification leads to a significant decrease of the electrical resistance and the polarization-sensitive transverse photocurrent in the films. It is also found that electrochemical hydrogenation significantly affects the ratio of the circular and the linear photocurrent components. The photocurrent is found to be generated on the subsurface layer of the films in the absence of crystalline phase component PdO.