Isolation and optoelectronic characterization of Si solar cells microstructure defects

This research article presents results of silicon solar cell defects optoelectronic characterization based on several experimental methods. These microstructure defects have their origin mainly in the production process, but also can be caused by mechanical stress. However, some defect related spots emit light when the cell is reverse biased. Therefore, electroluminescence (EL) method is used for macroscopic localization and scanning near-field optical microscopy (SNOM) combined with photomultiplier tube in order to scan topography of defective area in microscale. Moreover, elemental analysis of the defects related spots provided by energy-dispersive X-ray spectroscopy (EDX) is presented as well. Besides that, focused ion beam (FIB) was used to isolate the defective spots by 2 µm wide and 2 µm deep barrier. Isolation pattern around the defect is avoiding leakage current flow through it. Since leakage current does not flow through defect, solar cell parameters in reverse conditions are improved.