Atomistic Analysis Of Defect Interface Interactions In Silicon

Atomistic Analysis of Defect/interface Interactions in Silicon

Although multicrystalline silicon (mc-Si) currently is the most widely used material for fabricating photovoltaic cells, its electrical properties remain limited by several types of defects which interact in complex ways that are not yet fully understood. In particular, the influence of grain boundaries on the distribution of mobile impurities such as carbon and oxygen atoms, and native point defects (self-interstitials and vacancies), plays an important role in the formation of highly detrimental secondary-phase precipitates such as SiO 2 and SiC in mc-Si. While experimental methods mostly allow detection of precipitated defects, atomistic simulations additionally provide insight into the formation mechanisms of the defects, which may suggest pathways for preventing their generation. In the first part of this thesis, empirical molecular dynamics simulations are employed to study the interactions of twin grain boundaries with self-interstitials, vacancies and substitutional carbon atoms. It is shown that twin boundary-point defect interaction energies increase with twinning order and that they are predominantly attractive in nature. Moreover, twin boundary interactions with substitutional carbon are found to be highly spatially heterogeneous, exhibiting alternating repulsive-attractive regions that correlate strongly with the local bonding network. A robust, quantitative picture is obtained by comparing predictions across a total of five different empirical potentials.

TMS 2015 144th Annual Meeting and Exhibition

The TMS 2015 Annual Meeting Supplemental Proceedings is a collection of papers from the TMS 2015 Annual Meeting & Exhibition, held March 15-19 in Orlando, Florida, USA. The papers in this volume represent 33 symposia from the meeting. This volume, along with the other proceedings volumes published for the meeting, and archival journals, such as Metallurgical and Materials Transactions and Journal of Electronic Materials, represents the available written record of the 73 symposia held at TMS2015. This proceedings volume contains both edited and unedited papers; the unedited papers have not necessarily been reviewed by the symposium organizers and are presented "as is." The opinions and statements expressed within the papers are those of the individual authors only, and no confirmations or endorsements are intended or implied.

TMS 2015 144th Annual Meeting & Exhibition, Annual Meeting Supplemental Proceedings