Emerging Technologies in Crystal Growth of Photovoltaic Silicon: Progress and Challenges

The Photovoltaic (PV) market is dominated by crystalline silicon materials in the form of high-quality high-cost Czochralski monocrystalline silicon (mono-Si) and lower-cost defect-prone crucible-cast multicrystalline silicon (mc-Si). Therefore, development and commercialization of materials offering high efficiency cells at low cost is necessary for wider deployment of photovoltaic systems. Several alternative crystallization techniques aimed at lowering material-cost and improving energy conversion efficiency are being developed. These include Mono-like Silicon aimed at producing monocrystalline silicon (mono-Si) wafers using mc-Si technology, Kerfless Epitaxial Silicon (KE-Si) and Liquid to Wafer aimed at reduction of some of the process steps such as ingot growth and wafering, and Non-contact Crucible Silicon (NOC-Si) aimed at quality improvement of crucible-cast silicon through reduction of stress and impurity contamination during ingot growth. In this contribution, we review some of the prospects and challenges of Mono-like Silicon, NOC-Si and KE-Si techniques, focusing on content and impact of impurities and structural defects and overall electrical performance.