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2004
Conference Paper
Titel
Spatially resolved IR-measurement techniques for solar cells
Abstract
The article gives an overview over developments in the area of characterization tools for solar cells using CCD-cameras sensitive in the IR. Additionally, the prospects for the application of these measurement systems in In-Line and Off-Line process control will be addressed. The methods discussed include Dark and Illuminated Lock-In Thermography (DLT and ILT), Carrier Density Imaging (CDI) and Sheet Resistance Imaging (SRI). The two thermography-methods allow a spatially resolved investigation of leakage currents and power losses in solar cells under dark and illuminated conditions, respectively. CDI is the first measurement technique that provides a lifetime image with good spatial resolution within a few seconds to minutes and SRI permits the same quality and speed of measurements for the sheet resistance of solar cell emitters. All these techniques apply a CCD-camera sensitive in the IR and were developed to a state applicable in routine Off-Line cell characterization. An important common feature of all of them is that an imaging method replaces scanning the sample for obtaining good spatial resolution. Thus measurement times are significantly reduced as compared to previous setups, typically by a factor of 100 or above.