Deposition of antimony telluride thin film by ECALE

Abstract

The process of Sb 2 Te 3 thin film growth on the Pt substrate by electrochemical atomic layer epitaxy (ECALE) was studied. Cyclic voltammetric scanning was performed to analyze the electrochemical behavior of Te and Sb on the Pt substrate. Sb 2 Te 3 film was formed using an automated flow deposition system by alternately depositing Te and Sb atomic layers for 400 circles. The deposited Sb 2 Te 3 films were characterized by XRD, EDX, FTIR and FESEM observation. Sb 2 Te 3 compound structure was confirmed by XRD pattern and agreed well with the results of EDX quantitative analysis and coulometric analysis. FESEM micrographs showed that the deposit was composed of fine nano particles with size of about 20 nm. FESEM image of the cross section showed that the deposited films were very smooth and dense with thickness of about 190 nm. The optical band gap of the deposited Sb 2 Te 3 film was determined as 0.42 eV by FTIR spectroscopy, and it was blue shifted in comparison with that of the bulk Sb 2 Te 3 single crystal due to its nanocrystalline microstructure.

Deposition of Sb2Se3 thin films on Pt substrate via electro-chemical atomic layer epitaxy (EC-ALE)

“…This assumption is supported by the results presented just below that show the need for long polarization duration to observe the appearance of the stripping peak of bulk Sb. One can find similar electrochemical behavior of antimony in the literature [26][27][54][55]. Fig.…”

“…The concentrations of Sb2O3 and SeO2 were chosen based on both literature data and experimental observations. The concentration used in literature for Sb2O3 solutions [20,[24][25][26][27][28][29][30] ranges from 0.01 mM to 0.05mM, and we can confirm from experiment that 0.05 mM which is the most often used concentration, is higher than the solubility limit of antimony oxide in sulfuric acid solution. The concentration used in literature for SeO2 solutions [22,[31][32][33][34][35][36][37][38][39][40][41][42][43] ranges from 0.05 mM to 2 mM, with 0.5 mM as the most often used one.…”

“…Generally, as the alternative deposition progresses, the deposited part will generate additional resistance [26][27][54][55], which will cause the deposition potential to shift negatively. In our experiments, we tried different negatively-shifted potentials for deposition, and then determined the deposition potential of each layer according to the amount of stripping from anodic potentiodynamic scanning curve.…”

Underpotential deposition of selenium and antimony on gold

“…This stoichiometric ratio approximates that of the Sb 2 Se 3 compound. The slight difference could be due as already reported in literature [35,36] to the lattice misfit between gold and the deposit. Indeed, during the first 30-40 cycles, the deposit is aberrated and strained; it evolves toward a relaxed structure as the EC-ALE process goes on.…”