Recombination by grain-boundary type in CdTe

• Published in: Journal of applied physics 2015-07, Vol.118 (2)
• Main Authors: Moseley, John, Ahrenkiel, Richard K., Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, Metzger, Wyatt K., Moutinho, Helio R., Guthrey, Harvey L., Al-Jassim, Mowafak M., Paudel, Naba, Yan, Yanfa
• Format: Article
• Language: English
• Subjects: CADMIUM CHLORIDES; CADMIUM TELLURIDES; CATHODOLUMINESCENCE; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DIFFRACTION; GRAIN BOUNDARIES; LENGTH; RECOMBINATION; SPECTRA; SURFACES; THIN FILMS
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4926726

We conducted cathodoluminescence (CL) spectrum imaging and electron backscatter diffraction on the same microscopic areas of CdTe thin films to correlate grain-boundary (GB) recombination by GB “type.” We examined misorientation-based GB types, including coincident site lattice (CSL) Σ = 3, other-CSL (Σ = 5–49), and general GBs (Σ > 49), which make up ∼47%–48%, ∼6%–8%, and ∼44%–47%, respectively, of the GB length at the film back surfaces. Statistically averaged CL total intensities were calculated for each GB type from sample sizes of ≥97 GBs per type and were compared to the average grain-interior CL intensity. We find that only ∼16%–18% of Σ = 3 GBs are active non-radiative recombination centers. In contrast, all other-CSL and general GBs are observed to be strong non-radiative centers and, interestingly, these GB types have about the same CL intensity. Both as-deposited and CdCl{sub 2}-treated films were studied. The CdCl{sub 2} treatment reduces non-radiative recombination at both other-CSL and general GBs, but GBs are still recombination centers after the CdCl{sub 2} treatment.