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arXiv · 1111.5263

Insulator-to-Metal Transition in Selenium-Hyperdoped Silicon: Observation and Origin

Elif Ertekin·Mark T. Winkler·Daniel Recht·Aurore J. Said·Michael J. Aziz·Tonio Buonassisi·Jeffrey C. Grossman
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Abstract

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 sub-band gap optical absorption and metallicity in Se-hyperdoped Si. We show that sub-band gap absorption arises from direct defect-to-conduction 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 concentration in excellent agreement with experiment. Quantum Monte Carlo calculations confirm the critical concentration, demonstrate that correlation is important to describing the transition accurately, and suggest that it is a classic impurity-driven Mott transition.

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Elif Ertekin, Mark T. Winkler, Daniel Recht, Aurore J. Said, Michael J. Aziz, Tonio Buonassisi, Jeffrey C. Grossman. 2011-11-22. Insulator-to-Metal Transition in Selenium-Hyperdoped Silicon: Observation and Origin. https://doi.org/10.1103/physrevlett.108.026401

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