The differential efficiency of quantum-well lasers

Smowton, Peter M.; Blood, P.

doi:10.1109/2944.605699

Cited by 128 publications

(63 citation statements)

References 11 publications

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“…Preliminary investigations indicate that the injection problem arises in MCLEDs due to the limitations of the AlGaAs-based mirror surrounding the thin ͑one-lambda͒ AlGaInP-based active region, and due to electron confinement, which is a well-known obstacle for red VCSELs. [19][20][21] …”

Section: ͑4͒mentioning

confidence: 98%

“…3 It is well known that red AlGaInP-based MCLEDs and VCSELs suffer from bad injection efficiency compared to infrared AlGaAs-based emitters because of less favorable material properties such as smaller carrier confinement potential and larger effective masses. 19,20 It is then of great interest to determine the internal quantum efficiency of these devices so as to optimize the design of their active region. The first section of this article describes the design and the fabrication of the devices investigated.…”

Section: Introductionmentioning

confidence: 99%

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Experimental determination of the internal quantum efficiency of AlGaInP microcavity light-emitting diodes

Royo

Stanley

Ilegems

et al. 2002

Journal of Applied Physics

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Detailed study of external quantum efficiency ηQE is reported for AlGaInP-based microcavity light-emitting diodes (MCLEDs). Unlike conventional light-emitting diodes (LEDs) the extraction efficiency γext and far field profile depend on the linewidth of the intrinsic spontaneous emission and wavelength detuning between cavity mode and peak electroluminescence. This dependence makes it difficult to estimate the intrinsic spectrum, hence the performances of MCLEDs. By using a nondestructive deconvolution technique, the intrinsic spectra of a MCLED and a reference LED (with the same active regions) could be determined at different current densities. This allowed precise calculation of γext for both devices (values close to 11% were found for the MCLED), and hence of their apparent internal quantum efficiencies ηintapp. At 55 A/cm2, values of 90% and 40% were determined for the LED and MCLED, respectively. In order to explain this difference, we measured ηQE for devices with different sizes. From a fitting procedure based on a simple model taking into account the device size, we found that the radiative efficiencies of LEDs and MCLEDs were close to 90%. We concluded that the low ηintapp of MCLED was due to a bad current injection, and especially to electron leakage current, as confirmed by numerical simulations.

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Section: ͑4͒mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Experimental determination of the internal quantum efficiency of AlGaInP microcavity light-emitting diodes

Royo

Stanley

Ilegems

et al. 2002

Journal of Applied Physics

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“…Due to the significantly smaller ee of the hole in InGaAsN QW, the hh leakage is the dominant leakage mechanism for the InGaAsN QW. Severe thermionic carrier leakage leads to a reduction in the inj at threshold, 11,12 distinct from the above-threshold inj , 23 and will in turn lead to an increase in the J th of the QW laser.…”

mentioning

confidence: 99%

The role of hole leakage in 1300-nm InGaAsN quantum-well lasers

Tansu

Mawst

2003

Applied Physics Letters

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We calculate the thermionic escape times of electrons and holes in InGaAsN and InGaAs quantum wells using the most recent input data. The short thermionic escape time of holes from the InGaAsN quantum well indicates that hole leakage may be a significant factor in the poorer temperature characteristics of InGaAsN quantum-well lasers compared to those of InGaAs devices. We suggest a structure that results in an increased escape time, which will allow the reduction of hole leakage in these devices. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1558218͔The poor temperature characteristics of 1.3-m, InPbased semiconductor lasers have led to enormous efforts in exploring InGaAsN quantum-well ͑QW͒ lasers, 1-8 as an alternative to realize high-performance QW lasers for hightemperature operation. Early high threshold-current-density (J th ) 1300-nm InGaAsN single-quantum-well ͑SQW͒ lasers exhibit anomalously high T 0 (1/T 0 ϭ(1/J th )dJ th /dT) values, due to the large monomolecular recombination.9,10 Unfortunately, the T 0 values of the high-performance 1300-nm InGaAsN SQW lasers are only 70-110 K, [1][2][3][4][5]8 which is low compared to those of the 1200-nm InGaAs SQW lasers (T 0 ϭ200 K).1 The underlying cause for the relatively low T 0 values for InGaAsN lasers has not been conclusively determined. Recent analysis without taking account of carrier leakage processes, has attributed the low T 0 values to the existence of Auger recombination in the InGaAsN QW.10 In our earlier work, 9 the reduced T 0 andciency͒ values of the 1300-nm InGaAsN QW lasers, compared to 1190-nm InGaAs QW lasers, has been linked to an increase in the carrier/current leakage processes. Despite the deeper QW structure in the InGaAsN QW lasers, the experimentally measured current injection efficiency ( inj ) of 1300-nm InGaAsN QW reduces more rapidly with temperature compared to that of the 1200-nm InGaAs QW lasers. Here, we identify a carrier-leakage process in InGaAsN QW lasers 9 as heavy-hole ͑hh͒ leakage due to poor active-layer hole confinement.The thermionic carrier lifetime ( e ) in QW lasers is an important factor in determining the inj of a laser.11,12 A large thermionic lifetime of the carriers in the QW indicates a minimal escape rate of the carriers from the QW to the separate confinement heterostructure ͑SCH͒.11,12 Minimal thermionic carrier escape rate out of the QW will lead to an increase in inj and a reduction in the temperature sensitivity of inj .11,12 The conventional method to express the thermionic lifetime is based on the model by Schneider et al., 13 which utilizes the bulk ͓three-dimensional ͑3-D͔͒ density of states ͑DOS͒ and a simple parabolic band model. However, this model 13 has been shown to be insufficient to explain experiments, 14 and has a tendency to significantly overestimate the hole lifetime and to underestimate the electron lifetime.14 The thermionic lifetime model that we employ in this study is based on the model proposed by Irikawa et al.,14 that has been applied to the study of 1500-nm InGa͑Al͒A...

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“…The limitations of the efficiency of redemitting InAlGaP LEDs were attributed to the intrinsic constraint in the crossover from a direct bandgap to an indirect bandgap for InAlGaP materials, 268 which in turn limits the maximum band-offset achievable in InAlGaP-InGaP heterostructures. The low band-offset achievable in InAlGaP-InGaP increases thermally driven carrier leakage processes, 269,270 which has an impact on both the internal quantum efficiency and the current injection efficiency, in particular at high device operating temperatures. 271 Several approaches have been pursued to advance the InAlGaP technologies, specifically the development of active regions with increased spontaneous emission rate for high radiative efficiency and improved heterostructures for achieving higher current injection efficiency.…”

Section: Progress In Iii-v and Iii-nitride Semiconductor Lighting Tecmentioning

confidence: 99%

The role of photonics in energy

et al. 2015

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Abstract. In celebration of the 2015 International Year of Light, we highlight major breakthroughs in photonics for energy conversion and conservation. The section on energy conversion discusses the role of light in solar light harvesting for electrical and thermal power generation; chemical energy conversion and fuel generation; as well as photonic sensors for energy applications. The section on energy conservation focuses on solid-state lighting, flat-panel displays, and optical communications and interconnects.

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The differential efficiency of quantum-well lasers

Cited by 128 publications

References 11 publications

Experimental determination of the internal quantum efficiency of AlGaInP microcavity light-emitting diodes

Experimental determination of the internal quantum efficiency of AlGaInP microcavity light-emitting diodes

The role of hole leakage in 1300-nm InGaAsN quantum-well lasers

The role of photonics in energy

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