The thermoelectric properties of I-doped Bi2Te3 films grown by metal-organic chemical vapor deposition have been studied. I-doped epitaxial (00l) Bi2Te3 films were successfully grown on 4° tilted GaAs (001) substrates at 360 °C. I concentration in the Bi2Te3 films was easily controlled by the variation in a flow rate of H2 carrier gas for the delivery of an isopropyliodide precursor. As I ions in the as-grown Bi2Te3 films were not fully activated, they did not influence the carrier concentration and thermoelectric properties. However, a post-annealing process at 400 °C activated I ions as a donor, accompanied with an increase in the carrier concentration. Interestingly, the I-doped Bi2Te3 films after the post-annealing process also exhibited enhancement of the Seebeck coefficient at the same electron concentration compared to un-doped Bi 2Te3 films. Through doping I ions into Bi 2Te3, the thermopower was also enhanced in Bi 2Te3, and a high power factor of 5 × 10-3 W K-2 m-1 was achieved.
Bibliographical noteFunding Information:
This research was supported by the Korea Institute of Science and Technology (KIST) through the Converging Research Center Program through the Ministry of Education, Science and Technology (2012K001306).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry