Fast Cu(In,Ga)Se2 precursor growth: Impact on solar cell

In order to reduce the co-evaporation time of Cu(In,Ga)Se-2 (CIGSe) thin film absorber, a sequential approach has been investigated. CIGSe layers have been grown using the three-step based CUPRO (Cu-Poor/Rich/Off) process at substrate temperature of 600 and 500 degrees C. The first step consists in the growth of Cu-poor ([Cu]/[In + Ga] = 0.9) precursor layers. This paper aims at investigating the impact of this layer deposition duration on the CIGSe and respective solar cell properties. It is observed that for the two substrate temperatures investigated, the morphological and structural properties of the CIGSe layers do not change with increasing precursor deposition speed, even when it is increased by ten. Furthermore, the respective device performance also appears not affected by this reduction of the precursor growth time; all cells demonstrate 15% efficiency. From this work, the duration of our standard deposition process could be decreased from 23 to 14 min without performance loss independently of the substrate temperature. (C) 2011 Elsevier B.V. All rights reserved.