Reinterpretation of defect levels derived from capacitance spectroscopy of CIGSesolar cells
2009 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 7, 2153-2157 p.Article in journal (Refereed) Published
In this work we make an attempt to clarify ambiguities and to present our present understanding of defectsand defect-related phenomena affecting the capacitance characteristics of Cu(In,Ga)Se2-based solar cells. Wediscuss deep defect levels derived from admittance and deep level transient spectroscopy, as well as shallowlevels affecting the charge distributions by capacitance–voltage profiling. The discussion includes two typesof metastable effects affecting capacitance characteristics: one induced at room temperature by light orvoltage bias, and one created at low temperature by red illumination of reverse-biased junction (ROB effect).Recent theoretical achievements on negative-U properties of such intrinsic defects as selenium vacancies andInCu antisites are used to explain the experimental data. We show that the most prominent level in theadmittance spectra is due to the response of interface states combined with contribution of deep VSe–VCu−/2−acceptor level. We attribute the ROB metastability to the relaxation of InCu defects upon electron capture.Finally we discuss the influence of these defects on the device efficiency.
Place, publisher, year, edition, pages
Elsevier , 2009. Vol. 517, no 7, 2153-2157 p.
Condensed Matter Physics Engineering and Technology
Research subject Engineering Science with specialization in Electronics
IdentifiersURN: urn:nbn:se:uu:diva-120607DOI: 10.1016/j.tsf.2008.10.092ISI: 000263847300012OAI: oai:DiVA.org:uu-120607DiVA: diva2:303733