Thermotical Investigations of the Electronic and Thermoelectric Properties of Metal Oxide Materials

Student: Hind Alqurashi

Degree: Ph.D., May 2022

Major Professor: Dr. Bothina Manasreh

Research Area(s):

Microelectronics

Modeling & Simulation

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Background/Relevance

  • Thermoelectric (TE) materials are solid state devices that could be designed using two dissimilar materials such as n-type and p-type semiconductors. They are designed to convert thermal energy from a temperature gradient into electrical energy and visa versa.

  • Oxide materials are promising materials for TE applications due to their low cost, abundance and stability against decomposition at high temperatures.

Innovation

  • Using metal oxide materials in thermoelectric generators.

Approach

  • The density functional theory method is used to calculate the structural and electronic properties of the ZnO and CdO pure and alloyed oxides.
  • The semi-classical Boltzmann transport theory is used to calculate the thermoelectric properties that include seebeck coefficient, electrical conductivity, and electronic thermal conductivity of the materials.

Key Results

  • Electronic and thermoelectric properties of ZnxCd1-xO (x= 0.125, 0.25,0.375, 0.5, 0.625, 0.75, 0.875, and 1) alloys are investigated.
  • Using the GGA-PBE functional, ZnO exhibits direct band gap of 0.731 eV and CdO presents negative and indirect band gap of -0.501 eV, while using GGA-mbj, the band gap vales were improved to reach 2.670 eV for ZnO and 1.19 eV for CdO.

Conclusions

  • The metal oxide materials could be good semiconductor materials for thermoelectric devices because they have high Seebeck coefficient and a high thermal stability.

  • The band gaps of ZnxCd1-xO ternary alloys are improved using GGA-mbj hybrid functional as compared to the GGA-PBE functional.

Future Work

  • Phonon calculation to investigate stability of structure.

  • Calculating lattice thermal conductivity.

  • Calculating figure of merit.