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Title: EBSD of Rough Native CuInGaSe2 Thin-Films

Conference · · Microscopy and Microanalysis

The polycrystalline Cu (In, Ga) Se2, or CIGS, based thin-film materials system has long been studied for use in photovoltaic technologies, where its bandgap tunability, mechanical flexibility, and relatively low production costs are all appealing. Nonetheless, significant defect populations, which serve to reduce efficiency, create performance instabilities, and increase concerns about long-term reliability, have hindered wide-scale adoption. Prior work, including application of a scanning probe based deep level trap spectroscopy (SP-DLTS) defect mapping technique and scanning transmission electron microscope (STEM) based electron energy loss spectroscopy (EELS), has shown that the most detrimental defects, with energy level near mid-gap (thus serving as a carrier recombination center), are most likely caused by CuIn/Ga antisites and tend to cluster at or around certain grain boundaries [1,2]. However, the exact nature of these particular boundaries — their structures, chemistries, or even the relative misorientation of their associated grains — and their relation to this defect clustering and/or its formation is yet unknown. As such, electron backscatter diffraction (EBSD) orientation mapping, directly correlated with defect-sensitive techniques like SP-DLTS and/or STEM-EELS, could prove critical for providing the final missing links toward understanding the mechanisms behind these defects. Indeed, recent studies using correlative electron beam induced current (EBIC) with EBSD have been able to identify boundaries, and their relative misorientations, that possess detrimental electronic properties [3]. However, because EBIC is unable to resolve the defect energy levels, many questions are left unanswered. Furthermore, this study, and others like it, employed focused ion beam (FIB) milling to flatten the natively-rough CIGS [3-5], which may run the risk of changing the nature of any near-surface defect structures.

Research Organization:
The Ohio State Univ., Columbus, OH (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
DOE Contract Number:
EE0008755
OSTI ID:
1828496
Report Number(s):
10.1017/S1431927621011831
Journal Information:
Microscopy and Microanalysis, Vol. 27, Issue S1; Conference: Virtual; ISSN 1431-9276
Country of Publication:
United States
Language:
English

References (7)

Measurement of Grain Boundary Properties in Cu(ln,Ga)Se 2 Thin Films journal May 2018
Influence of Na on grain boundary and properties of Cu(In,Ga)Se 2 solar cells: Influence of Na on grain boundary and properties of Cu(In,Ga)Se 2 solar cells
  • Raghuwanshi, Mohit; Cadel, Emmanuel; Duguay, Sébastien
  • Progress in Photovoltaics: Research and Applications, Vol. 25, Issue 5 https://doi.org/10.1002/pip.2869
journal February 2017
Direct Nanoscale Characterization of Deep Levels in AgCuInGaSe 2 Using Electron Energy‐Loss Spectroscopy in the Scanning Transmission Electron Microscope journal August 2019
EMsoft: open source software for electron diffraction/image simulations journal July 2017
Interconnection between Trait, Structure, and Composition of Grain Boundaries in Cu(In,Ga)Se 2 Thin‐Film Solar Cells journal June 2020
Dictionary Indexing of Electron Back-Scatter Diffraction Patterns: a Hands-On Tutorial journal May 2019
Direct nm-Scale Spatial Mapping of Traps in CIGS journal September 2015

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