We report the near through mid-infrared (MIR) optical absorption spectra, over the range 0.05-1.3 eV, of monocrystalline silicon layers hyperdoped with chalcogen atoms synthesized by ion implantation followed by pulsed laser melting. A broad mid-infrared optical absorption band emerges, peaking near 0.5 eV for sulfur and selenium and 0.3 eV for tellurium hyperdoped samples. Its strength and width increase with impurity concentration. Its strength decreases markedly with subsequent thermal annealing. The emergence of a broad MIR absorption band is consistent with the formation of an impurity band from isolated deep donor levels as the concentration of chalcogen atoms in metastable local configurations increases. V C 2013 AIP Publishing LLC.
Articles you may be interested inCurrent-voltage characteristic and sheet resistances after annealing of femtosecond laser processed sulfur emitters for silicon solar cells Appl. Phys. Lett. 105, 053504 (2014); 10.1063/1.4892474 Deactivation of metastable single-crystal silicon hyperdoped with sulfur J. Appl. Phys. 114, 243514 (2013); 10.1063/1.4854835 Supersaturating silicon with transition metals by ion implantation and pulsed laser melting Electronic and structural properties of femtosecond laser sulfur hyperdoped silicon pn-junctions Appl. Phys. Lett. 103, 061904 (2013); 10.1063/1.4817726 Strong sub-band-gap infrared absorption in silicon supersaturated with sulfurThe authors demonstrate the formation of pn and nn + junctions based on silicon supersaturated with sulfur ͑up to 0.46 at. %͒ using a combination of ion implantation and pulsed laser melting. Silicon wafers were implanted at 200 keV 32 S + to doses ranging from 1 ϫ 10 15 to 1 ϫ 10 16 ions/ cm 2 and subsequently melted and resolidified by using a homogenized excimer laser pulse. Above a threshold laser fluence of ϳ1.4 J / cm 2 , the process produces a single crystal supersaturated alloy, free of extended defects, with a sharp junction between the laser melted layer and the underlying substrate, located near the maximum penetration of the melt front. Hall effect measurements indicate that the laser melted layers are n doped with a free carrier density up to 8 ϫ 10 18 /cm 3 that decreases by one-third upon postirradiation furnace annealing at 550°C. Dark current-voltage measurements performed on these structures show good rectifying behavior. The photovoltaic characteristics of the junctions were enhanced by postirradiation annealing at 550-800°C. These effects are attributed to the evolution of a population of point defects that survive the laser treatment. The influence of ion implantation dose, laser fluence, and annealing temperature on the properties of the junctions is also presented and discussed.
We present a novel approach to enhance light emission in Si and demonstrate a sub-bandgap light emitting diode based on the introduction of point defects that enhance the radiative recombination rate. Ion implantation, pulsed laser melting and rapid thermal annealing were used to create a diode containing a self-interstitial-rich optically active region from which the zero-phonon emission line at 1218 nm originates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.