Details

Autor(en) / Beteiligte

• Yoon, Ju-Heon
• Seong, Tae-Yeon
• Jeong, Jeung-hyun

Titel

Effect of a Mo back contact on Na diffusion in CIGS thin film solar cells

Ist Teil von

• Progress in photovoltaics, 2013-01, Vol.21 (1), p.58-63

Ort / Verlag

Bognor Regis: Blackwell Publishing Ltd

Erscheinungsjahr

2013

Quelle

Wiley Online Library

Beschreibungen/Notizen

• ABSTRACT We investigated the effects of the microstructures of molybdenum (Mo) back contacts on sodium (Na) diffusion from sodalime glass into a Cu(In,Ga)Se2 (CIGS) absorber as a function of the sputter deposition pressure during preparation of the Mo contact layer. The surface characteristics of the Mo layers more significantly affected the diffusion of Na ions into the CIGS compared with the Mo bulk. The Na ion diffusion depended strongly on the amount of oxygen adsorbed onto the Mo layer surfaces. Secondary ion mass spectroscopy results showed that Na accumulated in a layer (Na–O compound) on the Mo surface (the CIGS/Mo interface), and this layer served as a primary source of Na ions diffusing into the CIGS. A trilayered Mo back contact structure was prepared in an effort to decouple the functions of electrical conductance and Na diffusion. The ability of this surface to control the Na concentration in a CIGS absorber is discussed. Copyright © 2012 John Wiley & Sons, Ltd. Na diffusion in Cu(In,Ga)Se2 (CIGS) cells depends strongly on the surface microstructure of molybdenum (Mo) back contact. Mo back contact having less dense surface may enhance the Na doping of CIGS films because of higher oxygen content on the surface resulting in high accumulation of Na‐O compound. A trilayered Mo back contact, consisting of very thin surface layer and a conventional bilayer, can provide the better controllability for Na doping as well as electrical and mechanical properties.