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Your search keyword '"Parmar, Narendra S."' showing total 17 results
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17 results on '"Parmar, Narendra S."'

8. Hydrogen-related complexes in Li-diffused ZnO single crystals.

Author

Corolewski, Caleb D., Parmar, Narendra S., Lynn, Kelvin G., and McCluskey, Matthew D.

Subjects
*ZINC oxide, *SINGLE crystals, *HYDROGEN, *LITHIUM, *METAL complexes
Abstract

Zinc oxide (ZnO) is a wide band gap semiconductor and a potential candidate for next generation white solid state lighting applications. In this work, hydrogen-related complexes in lithium diffused ZnO single crystals were studied. In addition to the well-known Li-OH complex, several other hydrogen defects were observed. When a mixture of Li2O and ZnO is used as the dopant source, zinc vacancies are suppressed and the bulk Li concentration is very high (>1019cm-3). In that case, the predominant hydrogen complex has a vibrational frequency of 3677 cm-1, attributed to surface O-H species. When Li2CO3 is used, a structured blue luminescence band and O-H mode at 3327 cm-1 are observed at 10K. These observations, along with positron annihilation measurements, suggest a zinc vacancy–hydrogen complex, with an acceptor level ∼0.3 eV above the valence-band maximum. This relatively shallow acceptor could be beneficial for p-type ZnO. [ABSTRACT FROM AUTHOR]

Published
2016
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17. Sodium Acceptor Doping of ZnO Crystals.

Author

Parmar, Narendra S., Made Joni, I., and Lynn, Kelvin G.

Subjects
*ZINC oxide, *ZINC crystals, *DOPING agents (Chemistry), *SODIUM, *DIFFUSION
Abstract

ZnO bulk single crystals were doped with sodium by thermal diffusion using sodium dispensers. Secondaryion mass spectrometry measurement shows the diffusion of sodium with concentration ~ 1×1018 cm-3 in near surface region. Photoluminescence (PL) measurements show donor acceptor pair (DAP) emission at 408 nm at room temperature which exhibits a blue-shift to 404 nm at 9 K. DC Hall measurements show the mixed conduction due to low Hall voltage in these samples. PL measurements and variable temperature resistivity measurements suggest that the sodium acceptor activation energy is ~ 0.300 eV. [ABSTRACT FROM AUTHOR]

Published
2016
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