Ultra thin bismuth selenide-bismuth telluride layers for thermoelectric applications
- Resource Type
- Authors
- A. El-Khouly; Y. Keshkh; E.M. El Maghraby; Plamen Petkov; E. Lilov; A.M. Adam; V. Kovalyo; Moataz Soliman; Sh. Ebrahim
- Source
- Materials Chemistry and Physics. 224:264-270
- Subject
- Materials science
Scanning electron microscope
02 engineering and technology
010402 general chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
Microstructure
01 natural sciences
0104 chemical sciences
chemistry.chemical_compound
Thermal conductivity
chemistry
Seebeck coefficient
Thermoelectric effect
General Materials Science
Bismuth selenide
Bismuth telluride
Thin film
Composite material
0210 nano-technology
- Language
- ISSN
- 0254-0584
Crystalline thin films of Bi Te Se were deposited onto well cleaned glass substrates (BK7 type) by the vacuum thermal evaporation technique at a pressure of 10−3 Pa. Bulk samples were used as targets to evaporate the corresponding films. The internal microstructure of bulk samples and films were characterized by x-ray diffraction (XRD). Identifications of the microstructure and the surface morphology of the bulk and thin film samples were determined using scanning electron microscopy (SEM). Powder of the bulk alloys and the thin films of our products were observed to be polycrystalline in the form of hexagonal Bi2Se3 and Bi2Te3 structure. The material characteristic power factor of 74 μ W/mK2 was observed as the maximum value of power factor obtained in our study, and that was for Bi2Te3 near room temperature. The dimensionless figure of merit (ZT) was estimated based on Seebeck coefficient and electrical conductivity measurements alongside with thermal conductivity estimations. ZT values of Bi2Se3 and Bi2Se1.5Te1.5 were significantly enhanced as temperature increased, whilst, ZT of Bi2Te3 exhibited an opposite behavior. A mechanical stress test was performed in order to investigate the suitability of our films for thermoelectric modulus.