ORCID Profile
0000-0002-6379-3955
Current Organisation
University Of Strathclyde
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: AIP Publishing
Date: 2010
DOI: 10.1063/1.3276156
Abstract: We have systematically investigated the impact of device size scaling on the light output, spectral shift, and self-heating of 400 nm InGaN light-emitting diodes (LEDs). Devices with diameters in the range 20–300 μm have been studied. It is shown that smaller LED pixels can deliver higher power densities (despite the lower absolute output powers) and sustain higher current densities. Investigations of the electroluminescence characteristics of differently sized pixels against current density reveal that the spectral shift is dominated by blueshift at the low current density level and then by redshift at the high current density level, owing to the competition between the bandgap shrinkage caused by self-heating and band-filling effects. The redshift of the emission wavelength with increasing current density is much faster and larger for the bigger pixels, suggesting that the self-heating effect is also size dependent. This is further confirmed by the junction-temperature rise measured by the established spectral shift method. It is shown that the junction-temperature rise in smaller pixels is slower, which in turn explains why the smaller redshift of the emission wavelength with current density is present in smaller pixels. The measured size-dependent junction temperature is in reasonable agreement with finite element method simulation results.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2013
Publisher: Wiley
Date: 17-09-2013
Publisher: The Optical Society
Date: 13-02-2012
DOI: 10.1364/OME.2.000250
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2012
Publisher: AIP Publishing
Date: 04-03-2013
DOI: 10.1063/1.4794078
Abstract: We report modulation bandwidth measurements on a number of InGaN-based quantum well LEDs emitting at 450 and 520 nm wavelengths. It is shown that for these devices the data can be interpreted in terms of Auger recombination, by taking account of the carrier density dependence of the radiative coefficient. We find values for the Auger coefficient of (1±0.3)×10−29cm6s−1 at 450 nm and (3±1)×10−30cm6s−1 at 520 nm.
Publisher: AIP Publishing
Date: 10-2012
DOI: 10.1063/1.4757870
Abstract: Periodically nano-patterned organic films incorporating color converting light-emitting polymers have been integrated onto InGaN/GaN light-emitting diodes (LEDs). Polarized and strongly modified hybrid LED emission is observed due to the photonic crystal effect of the nano-pattern. Emission characteristics are appropriate for various applications, and fast modulation capability with an optical −3 dB bandwidth of 168 MHz is demonstrated.
Publisher: IEEE
Date: 10-2007
Publisher: Optica Publishing Group
Date: 08-12-2009
DOI: 10.1364/OE.17.023522
Publisher: The Optical Society
Date: 27-01-2011
DOI: 10.1364/OE.19.002720
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2010
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2012
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2009
Publisher: Optica Publishing Group
Date: 20-06-2008
DOI: 10.1364/OE.16.009918
Abstract: Micropixelated blue (470 nm) and ultraviolet (370 nm) AlInGaN light emitting diode ('micro-LED') arrays have been fabricated in flip-chip format with different pixel diameters (72 microm and 30 microm at, respectively, 100 and 278 pixels/mm(2)). Each micro-LED pixel can be in idually-addressed and the devices possess a specially designed n-common contact incorporated to ensure uniform current injection and consequently uniform light emission across the array. The flip-chip micro-LEDs show, per pixel, high continuous output intensity of up to 0.55 microW/microm(2) (55 W/cm(2)) at an injection current density of 10 kA/cm(2) and can sustain continuous injection current densities of up to 12 kA/cm(2) before breakdown. We also demonstrate that nanosecond pulsed output operation of these devices with per pixel onaxis average peak intensity up to 2.9 microW/microm(2) (corresponding to energy of 45pJ per 22ns optical pulse) can be achieved. We investigate the pertinent performance characteristics of these arrays for micro-projection applications, including the prospect of integrated optical pumping of organic semiconductor lasers.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jonathan McKendry.