Work

Electrodeposition and Thermoelectric Characterization of (00L)-Oriented Bi2Te3Thin Films on Silicon with Seed Layer

Year: 2013

Type: article

Abstract: Bi 2 Te 3 thin films were electrodeposited on silicon substrate with a epitaxial seed layer from acidic aqueous solutions at room temperature. The seed layer optimized the charge transfer in the electrodeposition process and reduced the lattice mismatch between the thin film and the substrate, leading to the Bi 2 Te 3 thin films with uniform structure and highly crystallographically texture. By changing the substrate from doped to intrinsic silicon, we obtained the Bi 2 Te 3 thin films with (00L) preferential orientation which is different from previously reported (015) or (110)-oriented thin films prepared by ECD. The (00L)-oriented thin film showed a more compact structure with lower roughness and an improved thermoelectric performance. The electrical conductivity increased by about 72% compared with the (110)-oriented thin film in our system. Simultaneously, the Seebeck coefficient was comparable, indicating the improvement of power factors by ∼45%. We also altered the thickness of the seed layer from 40 nm to 20 nm and found that both the electrical conductivity and Seebeck coefficient decreased due to the insufficient charge transfer in the electrodeposition process.

Source: Journal of The Electrochemical Society

DOI: 10.1149/2.099311jes