Effect of laser light polarisation on the dc photovoltage response of nanographite films

We report an experimental study of the influence of pulsed 1064-nm laser light polarisation on the dc photovoltage response of nanographite films. The amplitude of the pulsed potential difference generated in the films across the plane of incidence is an even function of the angle between the plane of polarisation and the plane of incidence of the laser beam, and that along the plane of incidence is an odd function of this angle. We present empirical relations between the incident pulse power, parameters of elliptically polarised laser light and photovoltage amplitude. The results are interpreted in terms of surface electric currents due to the quasi-momentum transfer from the incident light to the electron system via interband quantum transitions and the surface photogalvanic effect.