Winkler, Mark T.Recht, DanielSher, Meng-JuSaid, Aurore J.Mazur, EricAziz, Michael2014-08-262011Winkler, Mark T., Daniel Recht, Meng-Ju Sher, Aurore J. Said, Eric Mazur, and Michael J. Aziz. 2011. “Insulator-to-Metal Transition in Sulfur-Doped Silicon.” Physical Review Letters 106: 178701.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:12748663We observe an insulator-to-metal transition in crystalline silicon doped with sulfur to nonequilibrium concentrations using ion implantation followed by pulsed-laser melting and rapid resolidification. This insulator-to-metal transition is due to a dopant known to produce only deep levels at equilibrium concentrations. Temperature-dependent conductivity and Hall effect measurements for temperatures T>1.7  K both indicate that a transition from insulating to metallic conduction occurs at a sulfur concentration between 1.8 and 4.3×1020  cm−3. Conduction in insulating samples is consistent with variable-range hopping with a Coulomb gap. The capacity for deep states to effect metallic conduction by delocalization is the only known route to bulk intermediate band photovoltaics in silicon.en-USJournal Article2014-08-2610.1103/PhysRevLett.106.178701