Photoelectrochemical deposition of thin tellurium films

Effect of polychromatic light on the electrochemical deposition of tellurium(IV) ions on a glass carbon electrode from acid solutions of 0.45 M Na2SO4 + 0.05 M H2SO4 with pH 2.2 was studied. It is shown that electrochemical reduction of tellurium(IV) is possible in two stages in the potentiodynamic mode at potentials in the range from 0 to -1000 mV. Elementary tellurium is formed in the first stage (E = -320 +/- 20 mV) and is reduced to telluride ions in the second (E = -700 +/- 50 mV). It is demonstrated that, under potentiodynamic deposition conditions, visible light affects the generation of Te2- ions at potentials more positive than the electrochemical potential. The chronoamperometric method revealed differences in the behavior of transient currents in the dark and under illumination. The elemental composition and the film surface morphology were studied by electron-probe analysis.