The Phases and Morphology of Bi2Te3 Films Prepared by Electrodeposition

Thermoelectric materials Bi2Te3 films were synthesized by electrodeposition using Bi2O3 and TeO2 as raw materials. The effects of electrodeposition technologies on formation of Bi2Te3 phase were investigated under different deposition conditions. The phases of obtained products were analyzed by X-ray diffraction (XRD) and the size and morphology were observed by scanning electron microscope (SEM). Experimental results show that, when the deposition potential increases from 0.7 V to 0.8 V, the Bi2Te3 phase can be gotten in the product film with good crystallinity while it increases up to -0.9 V particle shedding phenomenon occurred; The film deposited by Bi-Te ratio 1:5 has good crystallinity with the highest XRD intensity and sharp peaks by comparing different Bi-Te ion ratios. With the deposition time increasing, the XRD intensity becomes higher for Bi2Te3 phase in the product films obtained by depositing 4 min, 10 min to 15 min while lower for the SnO2 layer on the substrates. The product film obtained at 50 degrees C has the highest crystallinity in the samples obtained at 30 degrees C, 40 degrees C and 50 degrees C. Lactic acid was the best additive for improving the quality of product films. Uniform and dense Bi2Te3 film with good crystallinity and particles size of 200 similar to 300 nm can be obtained under the deposition conditions of 50 degrees C, -0.8 V, 15 min and Bi-Te iron ratio 1:5.