Photovoltaic (PV) devices based on Cu(In,Ga)Se2-based (CIGS) absorber layers are one of the most promising thin-film solar cells. The addition of alkali elements to the CIGS material, especially sodium and potassium, has a beneficial effect on the cell conversion efficiency. SIMS offers quantitative depth profiling with a high depth resolution and a high analysis throughput. These features are essential to characterize CIGS solar cells, where possible variations in structure or composition can lead to higher overall conversion efficiencies.
In this study, CIGS thin films were prepared on bilayer Mo back contacts and deposited on a soda lime glass (SLG) substrate. The concentration of Na in the CIGS layer was controlled by using samples with and w/o a SiOx film on the SLG substrate. SIMS allowed to characterize the elemental in-depth distribution (matrix species & alkali metals Na and K) in the different CIGS thin films.
The IMS 7f-Auto provides high performance in terms of sensitivity, depth resolution, mass resolution, dynamic range and throughput. Characterization of the in-depth distribution in a solar cell multilayer structure with the IMS 7f-Auto proves extremely useful in addressing the various issues of multilayered PV material characterization: layer interface quality, doping concentration and distribution, impurity control…
Data collected on IMS 7f in KIST (Korea). From M. Kim et al., JVST B 34, 03H121 (2016).