Summary: Insulator-to-Metal Transition in Selenium-Hyperdoped Silicon: Observation and Origin
Elif Ertekin,1,* Mark T. Winkler,2,
Daniel Recht,3
Aurore J. Said,3
Michael J. Aziz,3
Tonio Buonassisi,2
and Jeffrey C. Grossman1,2,
1
Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, USA
2
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, USA
3
Harvard School of Engineering and Applied Sciences, Cambridge Massachusetts 02138, USA
(Received 14 October 2011; published 11 January 2012)
Hyperdoping has emerged as a promising method for designing semiconductors with unique optical and
electronic properties, although such properties currently lack a clear microscopic explanation. Combining
computational and experimental evidence, we probe the origin of sub­band-gap optical absorption
and metallicity in Se-hyperdoped Si. We show that sub­band-gap absorption arises from direct defect­
to­conduction-band transitions rather than free carrier absorption. Density functional theory predicts the
Se-induced insulator-to-metal transition arises from merging of defect and conduction bands, at a

Source: Aziz, Michael J.- School of Engineering and Applied Sciences, Harvard University

Collections: Physics; Materials Science