First principles modeling of grain boundaries in CdTe

Fatih G. Sen, Christopher Buurma, Tadas Paulauskas, Ce Sun, Moon Kim, Sivalingam Sivananthan, Robert F. Klie, Maria K.Y. Chan

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

Abstract

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.

Original languageEnglish
Title of host publication2016 IEEE 43rd Photovoltaic Specialists Conference, PVSC 2016
PublisherIEEE, Institute of Electrical and Electronics Engineers
Pages3374-3377
Number of pages4
Volume2016-November
ISBN (Electronic)9781509027248
DOIs
Publication statusPublished - 18 Nov 2016
Externally publishedYes
EventIEEE Photovoltaic Specialists Conference 2016 - Portland, United States of America
Duration: 5 Jun 201610 Jun 2016
Conference number: 43rd

Conference

ConferenceIEEE Photovoltaic Specialists Conference 2016
Abbreviated titlePVSC 2016
CountryUnited States of America
CityPortland
Period5/06/1610/06/16

Keywords

  • CdTe
  • density functional theory
  • grain boundaries

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