Anomalous X-ray Diffraction Studies for Photovoltaic Applications Metadata

Metadata describes a digital item, providing (if known) such information as creator, publisher, contents, size, relationship to other resources, and more. Metadata may also contain "preservation" components that help us to maintain the integrity of digital files over time.

Available Formats

Dublin Core: XML Dublin Core: JSON Dublin Core: Text Dublin Core: RDF/XML UNTL: XML Access METS: XML

Title

  • Main Title Anomalous X-ray Diffraction Studies for Photovoltaic Applications

Contributor

  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization

Publisher

  • Name: SLAC National Accelerator Laboratory
    Place of Publication: United States
    Additional Info: SLAC National Accelerator Laboratory (SLAC)

Date

  • Creation: 2011-06-22

Language

  • English

Description

  • Content Description: Anomalous X-ray Diffraction (AXRD) has become a useful technique in characterizing bulk and nanomaterials as it provides specific information about the crystal structure of materials. In this project we present the results of AXRD applied to materials for photovoltaic applications: ZnO loaded with Ga and ZnCo{sub 2}O{sub 4} spinel. The X-ray diffraction data collected for various energies were plotted in Origin software. The peaks were fitted using different functions including Pseudo Voigt, Gaussian, and Lorentzian. This fitting provided the integrated intensity data (peaks area values), which when plotted as a function of X-ray energies determined the material structure. For the first analyzed sample, Ga was not incorporated into the ZnO crystal structure. For the ZnCo{sub 2}O{sub 4} spinel Co was found in one or both tetrahedral and octahedral sites. The use of anomalous X-ray diffraction (AXRD) provides element and site specific information for the crystal structure of a material. This technique lets us correlate the structure to the electronic properties of the materials as it allows us to probe precise locations of cations in the spinel structure. What makes it possible is that in AXRD the diffraction pattern is measured at a number of energies near an X-ray absorption edge of an element of interest. The atomic scattering strength of an element varies near its absorption edge and hence the total intensity of the diffraction peak changes by changing the X-ray energy. Thus AXRD provides element specific structural information. This method can be applied to both crystalline and liquid materials. One of the advantages of AXRD in crystallography experiments is its sensitivity to neighboring elements in the periodic tables. This method is also sensitive to specific crystallographic phases and to a specific site in a phase. The main use of AXRD in this study is for transparent conductors (TCs) analysis. TCs are considered to be important materials because of their efficiency and low risk of environmental pollution. These materials are important to solar cells as a result of their remarkable combination of optical and electrical properties, including high electrical conductivity and high optical transparency in the spectrum of visible light. TCs provide a transparent window, which allows sunlight to pass through while also allowing electricity to conduct out of the cell. Spinel materials have the chemical form AB{sub 2}O{sub 4}, and are made of a face-centered cubic (FCC) lattice of oxygen anions and cations in specific interstitial sites. A normal spinel has all A cations on tetrahedral sites and B cations on octahedral sites. In contrast; an inverse spinel has the A and half of the B cations on octahedral sites and the other half of the B cations on tetrahedral sites; a mixed spinel lies between. In the spinel structure, 8 of 64 possible tetrahedral sites and 16 of 32 possible octahedral sites are filled. Normal spinels have particularly high conduction as the linear octahedral chains of B cations likely serve as conduction paths. In this paper we present how the data obtained with AXRD is used to analyze TCs properties as they apply to photovoltaic applications. One of the materials used for this analysis is zinc oxide. It has been loaded with 5% and 10% of Ga, which has an absorption edge of 10367 eV. The peak (100) was measured for the zinc oxide loaded with 10% Ga. In the case of 5% Ga, we measured peaks (100) and (101). With the information provided by the AXRD we can identify if Ga is being incorporated in the ZnO crystal structure. The analysis of 311 plane in the ZnCo{sub 2}O{sub 4} spinel shows if Co is in tetrahedral or octahedral site.

Subject

  • Keyword: Solar Cells
  • Keyword: Interstitials
  • Keyword: Probes
  • Keyword: Electrical Properties
  • Keyword: Oxygen
  • Keyword: Diffraction
  • Keyword: Electric Conductivity
  • Keyword: Spinels
  • Keyword: Pollution
  • Keyword: Origin
  • STI Subject Categories: 14 Solar Energy
  • Keyword: Crystallography
  • Keyword: X-Ray Diffraction
  • Keyword: Sensitivity
  • Keyword: Anions
  • Keyword: Scattering
  • Keyword: Absorption
  • Keyword: Crystal Structure
  • Keyword: Electricity
  • Keyword: Zinc Oxides Other
  • Keyword: Other
  • Keyword: Cations

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Report

Format

  • Text

Identifier

  • Report No.: SLAC-TN-11-013
  • Grant Number: AC02-76SF00515
  • DOI: 10.2172/1017216
  • Office of Scientific & Technical Information Report Number: 1017216
  • Archival Resource Key: ark:/67531/metadc836857

Note

  • Display Note: http://www.slac.stanford.edu/cgi-wrap/pubpage?slac-tn-11-013.html
Back to Top of Screen