Title:	Quantitative Assessment of TCO Sheet Resistance in Thin-Film Silicon Devices from Electroluminescence Images
Author(s):	G. Courtois, T. Fuyuki, A. Fuyuki, A. Salomon, P. Roca i Cabarrocas
Keywords:	Heterojunction, Electroluminescence, a-Si:H, Transparent Conductive Oxides
Topic:	THIN FILM SOLAR CELLS
Subtopic:	Silicon-based Thin Film Solar Cells
Event:	28th European Photovoltaic Solar Energy Conference and Exhibition
Session:	3CV.1.4
Pages:	2484 - 2488
ISBN:	3-936338-33-7
Paper DOI:	10.4229/28thEUPVSEC2013-3CV.1.4
Price:	0,00 EUR
Document(s):	paper, poster

Abstract/Summary:

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Once embedded in a thin-film module, the properties of the transparent conductive oxide (TCO) layer constituting the front electrode are uneasy to assess. We propose a method based on electroluminescence (EL) imaging which allows determining the sheet resistance (R) of this layer. For that purpose, we exploited EL intensity profiles across the device. From the experimental data, characteristic decay lengths (EL) of the logarithm of the EL intensity were extracted. On the other hand, assuming the elementary diodes constituting each cell were connected one to each other via the R of the front TCO, we could derive an analytical expression for the decay of the junction voltage across the cells, also exhibiting a characteristic decay length (V). Considering an exponential dependence of the EL intensity with respect to the local junction voltage, decay lengths were identified, thus providing an estimation of R, which proved to be twice greater than before the deposition process. As a perspective, the relevancy of applying this method to silicon heterojunction (SHJ) solar cells will be discussed.