Electrodeposition And Characterization Of Thin Selenium Films Modified With Lead Ad-atoms

摘要

The deposition and characterization of Se films doped with Pb underpotentially deposited (UPD) ad-atoms was studied in this work. The employed experimental techniques were cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, UV-vis spectroscopy and atomic force microscopy. The initial deposition of Se film by chronoamperometry yielded a thin film composed of approximately 700 layers. The Pb UPD on Se was achieved by chronoamperometry in a potential value previously determined in voltammetric experiments. This deposition yielded a deposition charge of approximately 7.5% of the total one. The film resistance altered from 320 Ω cm~(-2) for Se to 65 Ω cm~(-2) for the Se/Pb one. Flat band potential values and number of acceptors and donors were also calculated for both films and the values obtained were +0.95 and -0.51 V for Se and Se/Pb, respectively. The Se coating presented 1.2 × 10~(17) cm~(-3) acceptors while the Se/Pb one presented 3.2 × 10~(17) cm~(-3) donors. The band gap values for both films were 2.4 eV and 1.9 eV, correspondingly.