Photovoltaics,

364 IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 3, JULY 2012 Compositional Gradients in Cu(In,Ga)Se2 Thin Films for solar Cells and Their Effects on Structural Defects Jens Dietrich, Daniel Abou-Ras, Thorsten Rissom, Thomas Unold, Hans-Werner Schock, and Christian Boit, Member, IEEE diddleCu(In,Ga)Se2 (CIGSe) absorber layers used in thin?lm solar cells exhibit, when boast in a multistage process, compositional gradients of Ga and In. In this study, the correlational statisticss meet by the Ga gradient and the microstructure are studied by means of transmission electron microscopy (TEM) imaging combined with energy-dispersive roentgenogram spectroscopy (EDX), allowing the closing of structural defects and elemental distributions at same sample positions. The occurrence of linear defects (dislocations) and planar defects (stacking faults and microtwins) of CIGSe layers was studied by means of TEM images. The Ga distributions obtained from EDX elemental distrib ution maps and structural parameters from the publications were used to calculate the wicket gate parameters c and a and the gradient dc/dx perpendicular to the substrate. We raise a correlation between the magnitude of dc/dx and the occurrence of dislocations at canful individual large grains.

From the presented results, a threshold value of the Ga gradient of 1213at.%/?m can be estimated for the make-up of mis?t dislocations. proponent TermsChalcopyrite-type, Cu(In,Ga)Se2 (CIGSe), dislocation, Ga gradient, microstructure. I. INTRODUCTION HIN-FILM solar cells with polycrystalline Cu(In,Ga)Se2 (CIGS e) absorber layers and embedded in a ZnO/Cd! S/CIGSe/Mo/ nut case stack have reached powerconversion ef?ciencies of more than 20% [1], which is already similar with those of multicrystalline silicon solar cells [2]. CIGSe thin ?lms grown in a multistage coevaporation process exhibit compositional gradients of Ga and In. The Ga first appearance exhibits a local minimum of the [Ga]/([In]+[Ga]) (GGI) ratio...If you want to get a full essay, order it on our website: BestEssayCheap.com

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