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<creators>
<creator>
<creatorName>Rios, V.</creatorName>
<affiliation>Universitatea liberă din Berlin, Germania</affiliation>
</creator>
<creator>
<creatorName>Gurieva, G.A.</creatorName>
<affiliation>Universitatea liberă din Berlin, Germania</affiliation>
</creator>
<creator>
<creatorName>Schorr, S.</creatorName>
<affiliation>Universitatea liberă din Berlin, Germania</affiliation>
</creator>
</creators>
<titles>
<title xml:lang='en'>Chemical and structural characterization of offstoichiometric kesterite type selenides Cu2ZnSnSe4</title>
</titles>
<publisher>Instrumentul Bibliometric National</publisher>
<publicationYear>2014</publicationYear>
<relatedIdentifier relatedIdentifierType='ISBN' relationType='IsPartOf'></relatedIdentifier>
<dates>
<date dateType='Issued'>2014</date>
</dates>
<resourceType resourceTypeGeneral='Text'>Conference Paper</resourceType>
<descriptions>
<description xml:lang='en' descriptionType='Abstract'><p>Quaternary Cu2ZnSnSe4 (CZTSe) is a promising low cost alternative absorber material for thin film solar cells. A record efficiency of 12.6% was reported for a Cu2ZnSn(S,Se)4 (CZTSSe) based thin film solar cell [1]. The polycrystalline CZTSSe absorber layers exhibits an off-stoichiometric composition which causes intrinsic point defects (vacancies, anti-sites, interstitials). These defects determine the electronic properties of the material in a crucial way. This work focuses on the synthesis and characterization of off-stoichiometric CZTSe powder samples. In literature [2] different off-stoichiometric kesterite types have been suggested, so called; A-type: Cu-poor/Zn-rich, Cu2-2xZn1+xSnSe4 (x=0.025-0.125); B-type: Cu-poor/Sn-poor, Cu2- 2yZn1+3ySn1-ySe4 (y=0.025-0.075) and C-type: Cu-rich/Sn-rich, Cu2+2zZn1-3zSn1+zSe4 (z=0.025- 0.075). All powder samples were synthesized by solid state reaction from pure elements in sealed evacuated silica tubes in a one zone furnace. The first reaction took place at a temperature of 750&deg;C with several temperature holding steps (250&deg;C, 450&deg;C, 600&deg;C) in between. After reaction all samples were grinded, pressed in pellets and annealed again in evacuated and sealed silica tubes at 750&deg;C. In the ternary phase diagram Cu2Se-ZnSe-SnSe2 the single phase kesterite region is indicated to be very narrow [3], therefore the formation of secondary phases is highly expected. To determine phase content and chemical composition of the obtained samples, an electron microprobe system equipped with wavelength dispersive X-ray (WDX) analysis was used. The measurements proved the presence of CZTSe as main phase within all the different off-stoichiometric type synthesized samples. The lattice parameters a and c of the CZTSe main phase were determined by Rietveld analysis of XRD data collected using a PANalytical X‟pertPro MPD diffractometer. The Rietveld refinements were performed by FullProf software [4] using the kesterite structure model for the refinement procedure, because stoichiometric CZTSe crystallizes in the kesterite type structure [5]. A correlation between the occurrence of secondary phases and variation of the lattice parameters could be noticed (Figure 1); for instance the c/2a value is lower in samples containing SnSe2 compared with CuSe/Cu2Se containing samples. The samples in which secondary phases were not detected have higher a lattice parameter value. The study of the chemical composition, occurrence of secondary phases and structural properties of 3 different types of offstoichiometric CZTSe samples will be presented.</p></description>
</descriptions>
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<format>application/pdf</format>
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