Controllable crystal orientation is necessary to obtain high thermoelectric performance in thin films of Bi2Te3 alloys. In the present study, highly (110)-oriented thin films of n-type Bi2Te3-xSex with improved composition controllability are prepared through a simple electrodeposition-based process. Using potential-current co-adjusted pulse electrodeposition (PCP-ED) with adjustments to the zero current during the off-time period enables the fabrication of dense Bi2Te3-xSex thin films with highly (110)-oriented grains by minimizing the ionic gradient (Bi3+, Te2−, Se2−) between the substrate and solution. The power factor of the PCP-ED thin film was much higher than that of the dendritic Bi2Te3-xSex thin film fabricated by constant-potentiostatic electrodeposition (C-ED) because of the simultaneous enhancement of electrical conductivity and Seebeck coefficient. The high power factor of ∼1920 μW/m⋅K2, which is the best value among reported n-type Bi2Te3-based thin films, was obtained at room temperature after low-temperature annealing at 200 °C by exploiting the crystallinity enhancement and carrier concentration optimization.
Bibliographical noteFunding Information:
This work was supported by the Global Frontier Program through the Global Frontier Hybrid Interface Materials ( GFHIM ) project (grant number 2013M3A6B1078870 ) of the National Research Foundation of Korea ( NRF ), which is funded by the Ministry of Science, ICT, & Future Planning , and by the New & Renewable Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning ( KETEP ) (grant number 20153030013200 ). The Korea Research Fellowship (KRF) (grant number 2015H1D3A1066157 ) also supported this work. Appendix A
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry