Insulator-to-Metal Transition in Selenium-Hyperdoped Silicon: Observation and Origin
| Autor: | Ertekin, Elif, Winkler, Mark T., Recht, Daniel, Said, Aurore J., Aziz, Michael J., Buonassisi, Tonio, Grossman, Jeffrey C. |
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| Rok vydání: | 2011 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.108.026401 |
| Popis: | 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. Comment: 5 pages, 3 figures (PRL formatted) |
| Databáze: | arXiv |
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