Emergence of very broad infrared absorption band by hyperdoping of silicon with chalcogens

Abstract

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.

Picosecond carrier recombination dynamics in chalcogen-hyperdoped silicon

“…When heavy chalcogen (S, Se, or Te) dopants are incorporated into Si at concentrations near atomic percent level, the resulting material exhibits strong sub-band-gap light absorption. 11,12 The IMT has been experimentally observed in this system at N around 3 Â 10 20 cm…”

Deactivation of metastable single-crystal silicon hyperdoped with sulfur

“…3-5 Silicon hyperdoped with deep-level dopants (chalcogens, transition metals) has optoelectronic applications (photovoltaics, photodetectors, light emitters) [6][7][8][9] due to its enhanced broadband infrared absorption [10][11][12] and extended infrared photoresponse. 6,13 Hyperdoped silicon is a metastable, supersaturated solid solution.…”

Application of Ion Implantation for Intermediate Energy Levels Formation in the Silicon-Based Structures Dedicated for Photovoltaic Purposes

“…As it was assumed, occurrence of this new band could allow the photons of energy lower than E g to be absorbed, generating additional photocurrent and consequently, increasing the PV cells efficiency. The possibility of IB formation was confirmed experimentally for different impurities such as titanium [12], sulphur [13], selenium and tellurium [14]. Moreover, this may be be possible for other elements such as chalcogens or transition metals.…”

“…In this context, it is reasonable to investigate if it is possible to induce a shift in the value of E g using appropriately configured ion implantation and whether such operation will influence the performance of PV cells. Since the ion implantation and post-implantation treatment are the processes that require predetermining of a number of correlated variables, the aspect of consideration was a matter of many experimental and theoretical studies [11][12][13][14][15].…”