title: Insulator-to-metal transition in sulfur-doped silicon.
abstract: We 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 4.3×10(20)  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.
authors.affiliation: Department of Physics, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138, USA.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Winkler
authors.forename: Daniel
authors.initials: D
authors.lastname: Recht
authors.forename: Meng-Ju
authors.initials: MJ
authors.lastname: Sher
authors.forename: Aurore J
authors.initials: AJ
authors.lastname: Said
authors.forename: Eric
authors.initials: E
authors.lastname: Mazur
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Aziz