Abstract
In this work, we report a detailed material study of ultrafast laser textured silicon surfaces to gain insight into the impact of ultrafast laser processing conditions on photovoltaic device properties. A comprehensive study of the ultrafast laser processed silicon is achieved by determination of crystal structure and elemental compositional changes using transmission electron microscopy, compositional mapping by energy dispersive X-ray spectroscopy and depth profiling compositional determination using X-ray photoelectron spectroscopy. We have observed material non-homogeneity, impurity incorporation and strained silicon, all limited to the surface. A combination of chemical etching and thermal annealing was used to remove the laser induced changes and the material was restored to its starting quality. Further, silicon solar cell devices on such defect-etched surfaces are fabricated. These devices are characterized through dark iv analysis and Fourier transform deep level transient spectroscopy for defect analysis.
| Original language | English |
|---|---|
| Pages (from-to) | 2745-2751 |
| Number of pages | 7 |
| Journal | Solar Energy Materials and Solar Cells |
| Volume | 95 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2011 |
Funding
We would like to acknowledge the NASA Langley Professor Program , NSF I/UCRC Program and the Dean's office of the School of Engineering and Applied Science, University of Virginia , for financial support. Part of this research was supported by ORNL's CNMS and SHaRE User Facilities, which are sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, the U.S. Department of Energy . We would like to thank K. Shawn Reeves of ORNL for the FIB sample preparation required for TEM analysis. We are also thankful to Dr. H.-C. Yuan of the Silicon Materials and Devices group at NREL for initial fruitful discussions on device fabrication.
Keywords
- Defects
- Light trapping
- Solar cells
- Ultrafast laser processing
