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New Quantum Dots Findings Reported from Bhabha Atomic Research Center (H- ion implantation induced ten-fold increase of photoluminescence efficiency...

August 8, 2014



New Quantum Dots Findings Reported from Bhabha Atomic Research Center (H- ion implantation induced ten-fold increase of photoluminescence efficiency in single layer InAs/GaAs quantum dots)

By a News Reporter-Staff News Editor at Science Letter -- Current study results on Quantum Dots have been published. According to news reporting out of Maharashtra, India, by NewsRx editors, research stated, "We demonstrate a ten-fold increase in photoluminescence (PL) efficiency from 50 keV H- ion-implanted InAs/GaAs quantum dots (QDs) at a temperature of 8 K and/or 145 K. Enhancement occurred without post-annealing treatment. PL efficiency increased with increasing implantation fluence from 6 x 10(12) ions/cm(2) up to an optimum value of 2.4 x 10(13) ions/cm(2), beyond which PL efficiency decreased drastically (up to a fluence of 2.4 x 10(15) ions/cm(2))."

Our news journalists obtained a quote from the research from Bhabha Atomic Research Center, "Passivation of non-radiative recombination centres (due to direct interaction of H- ions with lattice defects) and de-excitation of photo-generated carriers to QDs through quantum mechanical tunnelling via H- ion-induced defects (e-traps) that are created near the QD-cap layer interface, resulted in PL efficiency enhancement. Shallow e-traps with activation energy similar to 90 meV and 30 meV created near the conduction band of GaAs cap layer for the samples implanted with H- of fluence 6 x 10(12) and 2.4 x 10(13) ions/cm(2) respectively are identified using low temperature PL study."

According to the news editors, the research concluded: "Contribution of de-trapped electrons from the e-traps to the QDs enhanced the PL efficiency at 145 K. Cross-section transmission electron microscopy and X-ray diffraction study revealed that the structural damage created by H- ions at the high fluence level of 2.4 x 10(15) ions/cm(2), caused the degradation in PL efficiency."

For more information on this research see: H- ion implantation induced ten-fold increase of photoluminescence efficiency in single layer InAs/GaAs quantum dots. Journal of Luminescence, 2014;153():109-117. Journal of Luminescence can be contacted at: Elsevier Science Bv, PO Box 211, 1000 Ae Amsterdam, Netherlands. (Elsevier - www.elsevier.com; Journal of Luminescence - www.elsevier.com/wps/product/cws_home/505700)

Our news journalists report that additional information may be obtained by contacting R. Sreekumar, Bhabha Atom Res Center, Div Nucl Phys, Bombay 400085, Maharashtra, India. Additional authors for this research include A. Mandal, S. Chakrabarti and S.K. Gupta (see also Quantum Dots).

Keywords for this news article include: Asia, India, Maharashtra, Quantum Dots, Nanotechnology, Quantum Physics, Emerging Technologies

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Science Letter


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