Sher, Meng-JuSimmons, Christie B.Krich, Jacob JonathanAkey, AustinWinkler, Mark T.Recht, DanielBuonassisi, TonioAziz, MichaelLindenberg, Aaron M.2015-10-052014Sher, Meng-Ju, Christie B. Simmons, Jacob J. Krich, Austin J. Akey, Mark T. Winkler, Daniel Recht, Tonio Buonassisi, Michael J. Aziz, and Aaron M. Lindenberg. 2014. “Picosecond Carrier Recombination Dynamics in Chalcogen-Hyperdoped Silicon.” Appl. Phys. Lett. 105 (5) (August 4): 053905. Portico. doi:10.1063/1.4892357.0003-6951http://nrs.harvard.edu/urn-3:HUL.InstRepos:22970215Intermediate-band materials have the potential to be highly efficient solar cells and can be fabricate by incorporating ultrahigh concentrations of deep-level dopants. Direct measurements of the ultrafast carrier recombination processes under supersaturated dopant concentrations have not been previously conducted. Here, we use optical-pump/terahertz-probe measurements to study carrier recombination dynamics of chalcogen-hyperdoped silicon with sub-picosecond resolution. The recombination dynamics is described by two exponential decay time scales: a fast decay time scale ranges between 1 and 200ps followed by a slow decay on the order of 1 ns. In contrast to the prior theoretical predictions, we find that the carrier lifetime decreases with increasing dopant concentration up to and above the insulator-to-metal transition. Evaluating the material’s figure of merit reveals an optimum doping concentration for maximizing performance.en-USJournal Article2015-10-0510.1063/1.4892357