FIB-SEM Investigations of the Microstructure of CIGS Solar Cells

Efficiency of thin-film copper indium gallium selenide (CIGS) solar cells is above 22 percent reaching the performance levels of modern polycrystalline silicon solar cells. Strong development efforts are ongoing to further increase cell efficiency. In this context, electron microscopy plays a crucial role because it allows the analysis of the microstructure of the solar cell through all relevant length scales and with very high resolution.

In this application note, high-efficiency thin-film solar cells based on Cu(In,Ga)Se₂ were studied extensively by focused ion beam – scanning electron microscopy (FIB-SEM) on a ZEISS Crossbeam. Cross sections of cells on different substrates were prepared by FIB to reveal the internal structure of the cell, allowing detailed characterization of the electrodes and microstructure throughout the cell by STEM, EDS and SIMS.