Les propriétés électrochimique et photoélectrochimique de semiconducteurs du groupe IV: Une cellule photoélectrochemique en germanium de type n

Abstract

Basing himself on the assumptions made in the works of B rattain, G arret, G erischer and T urner about the possibility of the photoelectrochemical effect appearing on a biased germanium electrode, the author started a certain number of experiments to determine the conditions under which the photoelectrochemical effect appeared and the factors affecting its maximum value. The author designed a miniature photoelectrochemical cell. The action of this cell is based on the photoelectrochemical effect appearing on the germanium n-type electrode, which is on reverse bias relative to the anode. When the potential difference between the germanium non-irradiated electrode and the auxiliary electrode of the cell is about 3–7 V (in 0·1M NaNO 2), the phenomenon of fall of potential difference between the electrodes to about 0–0·5 V occurs. The light sensitivity of the photoelement depends not only on the light intensity but also on the quantum energy. Maximum sensitivity occurs near the infra-red (0·85 μ). With reference to a photovoltaic cell in pure germanium, the evolved system is characterized by an increase in the photoelectrochemical effect as well as by the displacement of the maximum value of its spectral sensitivity towards shorter waves (from 1·5 μ for pure germanium to 0·85 μ for the biased germanium electrode).