Deposition of antimony telluride thin film by ECALE

摘要

The process of Sb_2Te_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_2Te_3 film was formed using an automated flow deposition system by alternately depositing Te and Sb atomic layers for 400 circles. The deposited Sb_2Te_3 films were characterized by XRD, EDX, FTIR and FESEM observation. Sb_2Te_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_2Te_3 film was determined as 0.42 eV by FTIR spectroscopy, and it was blue shifted in comparison with that of the bulk Sb_2Te_3 single crystal due to its nanocrystalline microstructure.