Retrograde melting in transition metal-silicon systems : thermodynamic modeling, experimental verification, and potential application

A theoretical framework is presented in this work for retrograde melting in silicon driven by the retrograde solubility of low-concentration metallic solutes at temperatures above the binary eutectic. High enthalpy of formation of point defects in silicon leads to retrograde solubility for a number of solutes, including many 3d transition metals. The Ni-Si system is used to demonstrate that in silicon under supersaturated conditions, such solutes precipitate out into liquid droplets. Synchrotron-based Xray Absorption Microspectroscopy measurements provide experimental confirmation of such phase transitions and the underlying thermodynamics. Finally, the potential for using retrograde melting to improve the electronic minority carrier lifetime of low quality silicon solar cell materials is considered.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Fenning, David P

Advisor dc:contributor.advisor

• Tonio Buonassisi.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/62530

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/62530