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

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.

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Low-intensity fetal lung on MRI imaging indicates pulmonary hypoplasia after 26 weeks' gestation.

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The drain current versus gate voltage characteristics of metal-oxide-semiconductor field-effect transistors (MOSFETs) with a silicon quantum-dot (QD) layer floating gate have shown the unique hysteresis and current bumps which arise from the electron charging or discharging of the QDs with an average dot height of 5 nm. The drain current response to application of a single-pulse gate bias has revealed that the multiple-step charging of the QD layer occurs until single electron occupation at each QD is achieved.