System for spectral characterization of solar cell structures

The spectral characterization system presented in this work is one based on a monochromator and it is able to deliver an under - millimeter spot size. The system is fully controlled by computer, shows good repeatability and high accuracy in spectral characterization of photovoltaic devices by the determination of internal quantum efficiency over an extended wavelength range. Two solutions for extended range detectors are explored in this study: pyroelectric and sandwich detectors. Most of the results shown in this abstract were obtained using a pyroelectric detector. The full version of the paper will show a comparison between the two types of detectors. Scanning images (maps) of internal quantum efficiency (IQE) and of external quantum efficiency (QE) can be obtained with high spatial resolution both in AC and DC mode. I-V curves can be obtained in monochromatic or white light in the same location as the IQE curves without a supplemental repositioning. Because IQE curves and I-V curves are obtained in the same location and using the same optics, a full characterization of the photovoltaic device under test is possible in a single run.