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Dive into the research topics where I Ahmad is active.

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Featured researches published by I Ahmad.


Journal of Applied Physics | 2008

Silicon nanocluster-sensitized emission from erbium: The role of stress in the formation of silicon nanoclusters

I Ahmad; M. P. Temple; A. Kallis; M Wojdak; Claudio J. Oton; D. Barbier; H. Saleh; Aj Kenyon; W.H. Loh

Erbium-doped silicon-rich silicon oxide films deposited by plasma enhanced chemical vapor deposition suffer from compressive stress as deposited, which converts to a large tensile stress on annealing due to the release of hydrogen. Although the cracking that results from this stress can be avoided by patterning the films into ridges, significant stress remains along the ridge axis. Measurements of erbium photoluminescence sensitized by silicon nanoclusters in stressed and relaxed films suggest an important role for internal film stresses in promoting the phase separation of excess silicon into nanoclusters, which has previously been thought of as a thermally driven process.


Physical Review B | 2008

Generalized rate-equation analysis of excitation exchange between silicon nanoclusters and erbium ions

Aj Kenyon; M Wojdak; I Ahmad; W.H. Loh; Claudio J. Oton


Journal of Luminescence | 2006

An analysis of erbium excited state absorption in silicon-rich silica

Aj Kenyon; W.H. Loh; Claudio J. Oton; I Ahmad


Materials Science and Engineering B-advanced Functional Solid-state Materials | 2008

Silicon nanoclusters containing nitrogen and sensitization of erbium luminescence in SiOx:Er

M Wojdak; I.I. Liaw; I Ahmad; Claudio J. Oton; W.H. Loh; Aj Kenyon; Ian W. Boyd


Presented at: E-MRS Fall 2010, Warsaw, Poland. (2010) | 2010

Sensitization of erbium photoluminescence and energy migration in erbium doped silicon-rich silica

M Wojdak; I Ahmad; H Saleh; Aj Kenyon; Claudio J. Oton; Mp Temple; W.H. Loh


In: (Proceedings) Fourth International Conference on Optical, Optoelectronic and Photonic Materials and Applications (ICOOPMA 10). (2010) | 2010

Sensitization of erbium photoluminescence in erbium doped silicon-rich silica with low Si excess

M Wojdak; I Ahmad; H Saleh; Aj Kenyon; Claudio J. Oton; Mp Temple; W.H. Loh


In: (Proceedings) Silicon Based Emission Technologies (SiBET) 2009. : Manchester. (2009) | 2009

(Invited) Silicon nanocluster sensitisation of erbium luminescence – time resolved measurements, nanocluster nucleation, and the role of stress.

Aj Kenyon; I Ahmad; Mp Temple; A Kallis; M Wojdak; Claudio J. Oton; H Saleh; W.H. Loh


In: (Proceedings) Impurity Based Electroluminescent Devices and Materials Conference. : Barcelona, Spain. (2009) | 2009

(Invited) Silicon Nanocluster-Sensitised Emission From Erbium – Photo- and Electro-luminescence Studies

Aj Kenyon; M Wojdak; I Ahmad; O. Jambois; Fabrice Gourbilleau; B. Garrido; R. Rizk


In: (Proceedings) European Materials Research Society Spring Meeting. : Strasbourg. (2009) | 2009

Long lifetime erbium luminescence sensitised by silicon nanoclusters

M Wojdak; I Ahmad; H Saleh; Mp Temple; Claudio J. Oton; Aj Kenyon; W.H. Loh


In: (Proceedings) IUMRS-ICEM 2008. : Sydney, Australia. (2008) | 2008

An Analysis of the Dynamics of Excitation Exchange between Silicon Nanoclusters and Erbium Ions.

Aj Kenyon; M Wojdak; I Ahmad; W.H. Loh; Claudio J. Oton

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Aj Kenyon

University College London

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M Wojdak

University College London

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W.H. Loh

University of Southampton

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Claudio J. Oton

Sant'Anna School of Advanced Studies

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A. Kallis

University College London

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H. Saleh

University College London

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I.I. Liaw

London Centre for Nanotechnology

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Ian W. Boyd

University College London

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M. P. Temple

University of Southampton

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B. Garrido

University of Barcelona

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