(Invited) Characterizing Defects in Semiconductors for Solar Cells and Understanding Their Impact on Device Performance

Abstract

Solar cells are intrinsically sensitive to minority carrier properties and therefore to intrinsic and extrinsic defects. This talk presents an overview of the application of microchemical, microstructural, and optoelectronic characterization techniques to observe these defects and connect their optoelectronic effects to the defect chemistry. This is particularly important in highly ionic materials and in materials that are applied as polycrystals where self-compensation, defect complexes, impurities segregated at grain boundaries, and second phases are critical. Therefore the talk will concentrate on those types of semiconductors. Scanning probe techniques and capacitance-based methods are particularly useful as they can probe within an individual grain even when that grain is small. Modeling to connect the individual defects to device performances is also described.