Insulator-to-Metal Transition in Selenium-Hyperdoped Silicon: Observation and Origin
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...
Main Authors: | , , , , , , |
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Other Authors: | , , , |
Format: | Article |
Language: | English |
Published: |
American Physical Society,
2012-07-10T14:53:37Z.
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Subjects: | |
Online Access: | Get fulltext |
Summary: | 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. United States. Dept. of Energy (Grant DE-SC0002623) National Center for Supercomputing Applications (Grant TG-DMR090027) National Science Foundation (U.S.) (Contract DMR 04-20415) United States. Army Research Office (Grant W911NF-10-1-0442) Army Armament Research, Development, and Engineering Center (U.S.) (Contract No. W15QKN-07-P-0092) |
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