In situ analysis of bismuth telluride electrodeposition using combined spectroscopic ellipsometry and electrochemical quartz crystal microbalance

Electrodeposition of bismuth telluride (Bi₂Te₃) in an acidic medium with Arabic gum by galvanostatic polarization has been investigated. Simultaneous in situ spectroscopic ellipsometry and gravimetric measurements have been performed to study the morphological evolution of the compound. A progressive covering stage was demonstrated and revealed that a 40 nm thick film has already acquired morphological and optical behavior similar to that of thicker films. The optical thickness and electrochemical quartz crystal microbalance (EQCM) mass are coherent with a density of 7.06. Combined gravimetric and coulometric data confirm the formation of Bi₂Te₃ by determining the ratio m/z.