Rapid annealing of reactively sputtered precursors for Cu2ZnSnS4 solar cells

• Published in: Progress in photovoltaics Vol. 22; no. 1; pp. 10 - 17
• Main Authors: Scragg, Jonathan J., Ericson, Tove, Fontané, Xavier, Izquierdo-Roca, Victor, Pérez-Rodríguez, Alejandro, Kubart, Tomas, Edoff, Marika, Platzer-Björkman, Charlotte
• Format: Journal Article
• Language: English
• Published: Bognor Regis Blackwell Publishing Ltd 01.01.2014; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Cu2ZnSnS4; CZTS; Electrical engineering, electronics and photonics; Electronics; Elektronik; Elektroteknik, elektronik och fotonik; Energy; Engineering Science with specialization in Electronics; Exact sciences and technology; kesterite; Natural energy; Photovoltaic conversion; reactive sputtering; Solar cells. Photoelectrochemical cells; Solar energy; sulfides; TECHNOLOGY; TEKNIKVETENSKAP; Teknisk fysik med inriktning mot elektronik; thin film solar cells; Performance evaluation; Grain size; Grain size analysis; Absorbent material; ZnSnS; kesterite; CZTS; High temperature; Rapid annealing; Tin sulfide; thin film solar cells; X ray diffraction; Zinc; Thin film; Metastable phase; Solar cell; Crystalline material; Zinc sulfide; Cu; Thin film cell; Copper sulfide; Reactive sputtering; Copper; sulfides
• ISSN: 1062-7995; 1099-159X; 1099-159X
• DOI: 10.1002/pip.2265

ABSTRACT Cu2ZnSnS4 (CZTS) is a promising thin‐film absorber material that presents some interesting challenges in fabrication when compared with Cu(In,Ga)Se2. We introduce a two‐step process for fabrication of CZTS films, involving reactive sputtering of a Cu‐Zn‐Sn‐S precursor followed by rapid annealing. X‐ray diffraction and Raman measurements of the sputtered precursor suggest that it is in a disordered, metastable CZTS phase, similar to the high‐temperature cubic modification reported for CZTS. A few minutes of annealing at 550 °C are sufficient to produce crystalline CZTS films with grain sizes in the micrometer range. The first reported device using this approach has an AM1.5 efficiency of 4.6%, with Jsc and Voc both appearing to be limited by interface recombination. Copyright © 2012 John Wiley & Sons, Ltd. Cu2ZnSnS4 is a promising thin‐film absorber material that presents some interesting challenges in fabrication when compared with Cu(In,Ga)Se2. Here, we demonstrate the development of large Cu2ZnSnS4 grains during rapid annealing of reactively sputtered Cu‐Zn‐Sn‐S precursor films. A metastable precursor phase is proposed to explain structural properties and the high rate of grain growth.