IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 4, NO. 2, MARCH2014 693 Characterization of Cu(In,Ga)Se 2 Electrodeposited and Co-Evaporated Devices by Means of Concentrated Illumination M. Paire, C. Jean, L. Lombez, T. Sidali, A. Duchatelet, E. Chassaing, G. Savidand, F. Donsanti, M. Jubault, S. Collin, J.-L. Pelouard, D. Lincot, and J.-F. Guillemoles Abstract—We present a new Cu(In,Ga)Se 2 characterization tool: Cu(In,Ga)Se 2 microcells. By creating pixels on a Cu(In, Ga)Se 2 substrate, we are able to test electrically different loca- tions. Moreover, because of the reduced size of the cells, (5-to 500-μm wide), heat and spreading resistance losses are made negli- gible, which make high flux characterizations available. We analyze current–voltage curves under high concentration to gain insight in the physical properties of Cu(In,Ga)Se 2 cells. From our analysis, Cu(In,Ga)Se 2 electrodeposited absorbers present resistivity fluc- tuations that are much more important than co-evaporated ones. These absorbers, as they present more electronic defects, are also more affected by the V oc increase under intense fluxes, and the ef- ficiency gains can be very significant: up to 6% absolute efficiency points at less than 50 suns. Index Terms—Current–voltage characteristics, photovoltaic cells. I. INTRODUCTION T HE chalcopyrite compound Cu(In,Ga)Se 2 has proven to be very efficient as a solar cell absorber, with over 20% efficiency reached in 2011 [1]. Various techniques are available to synthesize Cu(In,Ga)Se 2 , such as co-evaporation, sputtering, electrodeposition, and printing, to name a few. Each absorber deposition process leads to distinct opto-electronic properties of the corresponding solar cells. It is thus important to have characterization tools that can link final devices characteristic to features of the deposition process. In this paper, we propose to compare Cu(In,Ga)Se 2 solar cells with either co-evaporated or electrodeposited absorbers. In order to gain insight into the Manuscript received June 10, 2013; revised November 27, 2013; accepted November 28, 2013. Date of publication January 2, 2014; date of current version February 17, 2014. M. Paire, T. Sidali, A. Duchatelet, G. Savidand, F. Donsanti, and M. Jubault, are with the EDF R&D, Institute of research and development on photovoltaic energy–IRDEP, F-78401 Chatou, France (e-mail: myriam. paire@gmail.com; tarik.sidali@edf.fr; aurelien.duchatelet@edf.fr; gregory. savidand@edf.fr; frederique.donsanti@edf.fr; marie.jubault@edf.fr). C. Jean, L. Lombez, E. Chassaing, D. Lincot, and J.-F. Guillemoles are with the CNRS Institute of research and development on photovoltaic energy–IRDEP, F-78401 Chatou, France (e-mail: cyril-externe.jean@edf.fr; laurent-lombez@chimie-paristech.fr; elisabeth-chassaing@chimie-paristech. fr; daniel-lincot@chimie-paristech.fr; jf-guillemoles@chimie-paristech.fr). S. Collin, and J-L. Pelouard are with the CNRS, Laboratoire de photonique et nanostructures–LPN, F-91460 Marcoussis, France (e-mail: st´ ephane.collin@lpn.cnrs.fr; jean-luc.pelouard@lpn.cnrs.fr). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JPHOTOV.2013.2293889 differences between these two processes, we use a novel tech- nique. We characterize a pixilated substrate under various il- lumination conditions (dark, AM1.5 G, or concentrated illu- mination). Conclusions on material quality, homogeneity, or sensitivity to temperature elevation are given. II. F ABRICATION AND CHARACTERIZATION METHODS A. Approach Cu(In,Ga)Se 2 solar cells are studied by creating pixels on a large substrate. Thus, local characterization of opto-electronic properties is possible. The cells studied here are of the type sodalime glass/Mo/Cu(In,Ga)Se 2 /CdS/ZnO/ZnO:Al, where Mo and ZnO layers are deposited by sputtering and CdS by chemical bath deposition. Two types of absorbers are used in this study. B. Absorber Synthesis Two different Cu(In,Ga)Se 2 absorber synthesis processes are compared in this paper. The first absorber type is obtained by co-evaporation, in a three-stage process, as described in [2]. The second process is the electrodeposition of Cu(In,Ga)Se 2 precursors and subsequent annealing. The electrodeposition is carried out in a single step, in an aqueous solution of Cu(II), In(III), and Ga (III) nitrates [3]. The precursor layer is then transformed in a metallic layer by annealing in a reducing at- mosphere (H 2 containing atmosphere). The Cu(In,Ga)Se 2 layer is formed after selenization by annealing in a selenium saturated atmosphere. This process can give on conventional laboratory cells (0.1 cm 2 ) around 10% efficiency [3]. C. Microcells Fabrication The CdS and ZnO layer are subsequently deposited by chem- ical bath deposition and sputtering. In order to pixelate the sub- strate, microcells are created by using a patterned insulating layer. A SiO 2 layer is deposited on top of the ZnO layer prior to the deposition of ZnO:Al and patterned by UV-lithography. Thus, microdiodes are only created in the holes patterned in the insulating layer. More details on the patterning process can be found elsewhere [4]. The microcell size varies from 500-μm down to less than 10-μm in diameter. On each sample, 244 microcells are pat- terned. The pixels are distant from one another by 1 mm. 2156-3381 © 2014 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications standards/publications/rights/index.html for more information.