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Title: Point defects in Cu 2ZnSnSe 4(CZTSe): Resonant X-ray diffraction study of the low-temperature order/disorder transition

We report that the interest in Cu 2ZnSn(S,Se) 4 (CZTS) for photovoltaic applications is motivated by similarities to Cu(In,Ga)Se 2 while being comprised of non-toxic and earth abundant elements. However, CZTS suffers from a V oc deficit, where the V oc is much lower than expected based on the band gap, which may be the result of a high concentration of point-defects in the CZTS lattice. Recently, reports have observed a low-temperature order/disorder transition by Raman and optical spectroscopies in CZTS films and is reported to describe the ordering of Cu and Zn atoms in the CZTS crystal structure. To directly determine the level of Cu/Zn ordering, we have used resonant-XRD, a site, and element specific probe of long range order. We used CZTSe films annealed just below and quenched from just above the transition temperature; based on previous work, the Cu and Zn should be ordered and highly disordered, respectively. Our data show that there is some Cu/Zn ordering near the low temperature transition but significantly less than high chemical order expected from Raman. Finally, to understand both our resonant-XRD results and the Raman results, we present a structural model that involves antiphase domain boundaries and accommodates the excessmore » Zn within the CZTS lattice.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [3] ;  [3] ;  [5]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States). Applied Energy Programs
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  4. Stanford Univ., CA (United States). Materials Science and Engineering Department
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States). Applied Energy Programs and Stanford Synchrotron Radiation Lightsource
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AC36-08-GO28308; ECCS-1542152; DGE-1656518
Type:
Accepted Manuscript
Journal Name:
Physica Status Solidi B. Basic Solid State Physics
Additional Journal Information:
Journal Volume: 254; Journal Issue: 9; Journal ID: ISSN 0370-1972
Publisher:
Wiley-Blackwell
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 14 SOLAR ENERGY; Cu2ZnSnSe; order–disorder transitions; point defectes; thin films; X-ray diffraction
OSTI Identifier:
1395248
Alternate Identifier(s):
OSTI ID: 1390346