Citation
Hofstetter, Jasmin and Cañizo Nadal, Carlos del and Wagner, Hannes and Castellanos, Sergio and Buonassisi, Tonio
(2016).
Material requirements for the adoption of unconventional silicon crystal and wafer growth techniques for high-efficiency solar cells.
"Progress in Photovoltaics: Research and Applications"
;
ISSN 1062-7995.
https://doi.org/10.1002/pip.2699.
Abstract
Silicon wafers comprise approximately 40% of crystalline silicon module cost, and represent an area of great technological innovation potential. Paradoxically, unconventional wafer-growth techniques have thus far failed to displace multicrystalline and Czochralski silicon, despite four decades of innovation. One of the shortcomings of most unconventional materials has been a persistent carrier lifetime deficit in comparison to established wafer technologies, which limits the device efficiency potential. In this perspective article, we review a defect-management framework that has proven successful in enabling millisecond lifetimes in kerfless and cast materials. Control of dislocations and slowly diffusing metal point defects during growth, coupled to effective control of fast-diffusing species during cell processing, is critical to enable high cell efficiencies. To accelerate the pace of novel wafer development, we discuss approaches to rapidly evaluate the
device efficiency potential of unconventional wafers from injection-dependent lifetime measurements.