Ion beam analysis of Cu(In,Ga)Se2 thin film solar cells

•Elemental depth profiles for various CIGS thin films were quantitatively determined.•Pure absorbers, complete cell and bilayer solar cells were prepared and analyzed.•Synergistic PIXE and RBS analysis of thin solar cells using alpha beam particles.•High energy alpha beam resolved completely the Indium depth profile.•Synchrotron based Reference Free GIXRF quantitative analysis validated IBA results. The present work investigates the potential of ion beam analysis (IBA) techniques such as the Rutherford backscattering spectrometry (RBS) and particle induced X-ray emission (PIXE) using helium ions to provide quantitative in-depth elemental analysis of various types of Cu(In,Ga)Se2 thin films. These films with a thickness of about 2μm are used as absorber layers in photovoltaic devices with continuously increasing the performance of this technology. The preparation process generally aims to obtain an in-depth gradient of In and Ga concentrations that optimizes the optoelectronic and electrical properties of the solar cell. The measurements were performed at directly accessible single or double layered CIGS absorbers and at buried absorbers in completed thin film solar cells. The IBA data were analyzed simultaneously in order to derive best fitted profiles that match all experimental RBS and PIXE spectra. For some samples elemental profiles deduced form synchrotron based, reference free grazing incidence X-ray fluorescence analysis were compared with the IBA results and an overall good agreement was observed within quoted uncertainties.