Jonathan Heffernan
University of Oxford
48 Papers
465 Citations
Jonathan Heffernan is an academic researcher from University of Oxford. The author has contributed to research in topics: Molecular beam epitaxy & Layer (electronics). The author has an hindex of 11, co-authored 48 publications.
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Papers
Patent
Solid state illumination system
Rakesh Roshan,Benjamin James Hadwen,David James Montgomery,Jonathan Heffernan +3 more
- 23 Mar 2008
TL;DR: In this article, an illumination system consisting of at least two light sources (101,102,103) having different emission spectra to one another, a detection circuit (131,132,133) for sensing a light intensity using at least one of the light sources as a photosensor; and driving means (161,162,163) for driving the light source in dependence on the sensed spectral distribution of light.
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InGaN multiple quantum well laser diodes grown by molecular beam epitaxy
S. E. Hooper,Matthias Kauer,Valerie Bousquet,Katherine L. Johnson,Jennifer Mary Barnes,Jonathan Heffernan +5 more
TL;DR: In this article, the first InGaN multiple quantum well laser diodes produced by molecular beam epitaxy were demonstrated at room temperature under pulsed current injection conditions at a wavelength of approximately 400 nm with a spectral line width of less than 0.2 nm.
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Patent
Method of growing a semiconductor layer
Jennifer Mary Barnes,Valerie Bousquet,Stewart Edward Hooper,Jonathan Heffernan +3 more
- 13 Jun 2002
TL;DR: In this paper, a method of growing a p-type nitride semiconductor material having magnesium as a p type dopant by molecular beam epitaxy (MBE) comprises supplying ammonia gas, gallium and magnesium to an MBE growth chamber containing a substrate, so as to grow a ptype GaN material over the substrate.
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Strong carrier confinement in In x Ga 1 − x N ∕ Ga N quantum dots grown by molecular beam epitaxy
TL;DR: In this paper, the authors showed photoluminescence from single quantum dots, giving an unambiguous proof of the quantum dot nature of luminescence, and they showed that both the luminance intensity and the carrier recombination time remain constant up to $200\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, reflecting the strong confinement of the carriers inside the quantum dots.
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Continuous-wave operation of InGaN multiple quantum well laser diodes grown by molecular beam epitaxy
Matthias Kauer,S. E. Hooper,Valerie Bousquet,Katherine L. Johnson,C. Zellweger,Jennifer Mary Barnes,J. Windle,Tim Michael Smeeton,Jonathan Heffernan +8 more
TL;DR: In this paper, the first continuous-wave InGaN multiple quantum well laser diodes grown by molecular beam epitaxy are reported, which have a threshold voltage of 8.6 V and lase at a wavelength of /spl sim/405 nm for >3 min at 20/spl deg/C.
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