Nanogravimetric study of lead underpotential deposition on selenium thin films as a semiconductor alloy formation procedure

Abstract

An electrochemical quartz crystal microbalanceAu electrode modified with a Se thin film was used to investigate the electrochemical behavior of lead ad-atoms using underpotential deposition (UPD) conditions. A specific quasi-reversible process was observed during the reduction of Pb²⁺ on Se thin films in perchloric acid media. The charge density of Pb ad-atoms on Se thin film (46.86 μC cm⁻²) suggests a recovery of 0.1 monolayers, which is in good agreement with EQCM data. The Se thin film can be successfully alloyed with Pb atoms that are deposited by chronoamperometry using time intervals large enough to allow for diffusion toward the inner Se phase. Linear sweep voltammetry combined with EQCM in perchloric acid was used to characterize the amount of Pb absorbed in the Se thin film. These findings offer a new strategy for alloy formation in semiconductor films using UPD as an effective tool to quantify the exact amount of the incorporated metal.