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

• Main Authors: Ertekin, Elif (Contributor), Winkler, Mark Thomas (Contributor), Recht, Daniel (Author), Said, Aurore J. (Author), Aziz, Michael J. (Author), Grossman, Jeffrey C. (Contributor), Buonassisi, Anthony (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Materials Science and Engineering (Contributor), Massachusetts Institute of Technology. Department of Mechanical Engineering (Contributor), Massachusetts Institute of Technology. Laboratory for Manufacturing and Productivity (Contributor), Buonassisi, Tonio (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2012-07-10T14:53:37Z.
• Subjects: Article
• Online Access: Get fulltext

 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.