First principles modeling of grain boundaries in CdTe
| Autor: | Fatih Şen, Ce Sun, Sivalingam Sivananthan, Christopher Buurma, Maria K. Y. Chan, Robert F. Klie, Tadas Paulauskas, Moon J. Kim |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Condensed matter physics 05 social sciences 050301 education 02 engineering and technology Electronic structure 021001 nanoscience & nanotechnology Crystallographic defect Hybrid functional Characterization (materials science) Condensed Matter::Materials Science Crystallography Density functional theory Grain boundary Charge carrier Dislocation 0210 nano-technology 0503 education |
| Zdroj: | 2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC). |
| Popis: | A fundamental understanding of the role of vacancies, interstitials, dislocations and grain boundaries on the electronic structure of CdTe may lead to efficiency improvements. Atomistic-level characterization, including microscopy and first principles modeling, is crucial in developing such a fundamental understanding. In the present work, we built atomistic grain boundary and dislocation core models directly from the STEM images using image analysis methods and crystallographic information at the interface. Grain boundaries are modeled using first principles density functional theory (DFT) calculations. Electronic structures of large-scale grain models are also computed with an accurate hybrid functional (HSE06). We report the electronic density of states (DOS) and electrostatic potential profiles of different CdTe grain boundaries to understand charge carrier interactions. Thermodynamics of point defects and pairs of point defects that can exist on or near grain boundaries are studied and pertaining changes in electronic structure are reported. The implications of these electronic structure changes at grain boundaries on photovoltaic performance, and corresponding strategies to improve performance, are discussed. |
| Databáze: | OpenAIRE |
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