Investigation of defects in solar cells and wafers by means of magnetic measurements

摘要

Characterization tools play an important role for the further improvement and development of solar cells. A huge variety of highly advanced methods already exists, mainly based on optical and electrical measurements. However, the direct measurement of surface currents by the detection of their induced magnetic fields has gained less attention. We present a novel method, Current-Analysis-by-Inductive-Coils (CAIC), based on an inductive coil detector and compare it with already established methods, like Light-Beam-Induced-Current (LBIC) and Lock-In- Thermography (LIT). The CAIC detector reveals complementary information at high resolution. LIT measurements were carried out depicting shunting defects at forward and reverse bias. Due to the high spatial resolution of the CAIC measurement technique current sinks were identified revealing a better understanding of the electric activity of precipitates. LBIC measurements on grain boundaries allow for comparison of the resulting internal quantum efficiency with the electric activity determined by CAIC measurements.