Tailoring the thermoelectric properties of bulk ZnAlO with different aluminum concentrations (1, 1.5 and 2%) by post annealing in air at various temperatures

• Published in: Physica. B, Condensed matter Condensed matter, 2021-02, Vol.603, p.412727, Article 412727
• Main Author: Alzaid, Meshal
• Format: Article
• Language: English
• Subjects: Aluminum; Annealing; Annealing temperature; Carrier mobility; Conductivity; Crystal structure; Doping; Electrical resistivity; Hall effect; High temperature; Hydraulic presses; Lattice scattering; Pallets; Raman spectroscopy; Seebeck effect; Seebeck method; Temperature; Thermoelectric power generation; Thermoelectricity; XRD; Zinc oxide; Zinc oxides; ZnAlO alloy
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2020.412727

In current research work we have able to enhanced the thermoelectric power generation ability of ZnO using two different methods simultaneously i. e alloying with Al atoms and post growth annealing method. ZnAlO alloy having different Al concentration (1, 1.5 and 2%) was converted into pallets after mixing Al and zinc oxide powders using hydraulic press having 13 tons pressure. The prepared pellets were subjected to high temperature annealing ranging from 700-900oC with step of 50 °C for each doping concentration. The crystal structure of all un-annealed and annealed samples was verified by XRD and Raman spectroscopy measurements. Seebeck data suggested that ZnAlO sample with 1% Al concentration and annealed at 700 °C has a maximum value of Seebeck coefficient 481 μV/°C and this value was enhanced to 1017 μV/°C as the measurement temperature increase from 25 °C to 100 °C. The electrical conductivity measured using Hall Effect showed an increasing trend with an increase in doping concentration as well as with post annealing temperature. The observed behavior of Seebeck coefficient and electrical conductivity with Al atoms concentration and annealing temperature suggested the enhancement of carrier mobility. The optimized values of Al concentration (1%) and annealing temperature (700 °C) are due to the fact that carrier scattering phenomena changes from lattice scattering to impurity scattering.