Ultimate limit and temperature dependency of light-emitting diode efficiency

Heikkilä, Oskari; Oksanen, Jani; Tulkki, Jukka

doi:10.1063/1.3125514

Cited by 71 publications

(63 citation statements)

References 33 publications

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“…[1][2][3] In this scenario, the wall-plug efficiency (WPE, η W P E ) of the LED is over 100% and net cooling might be observed. The phenomenon is called electroluminescent cooling (ELC) and has been studied for over half a century.…”

Section: Previous Work On Ultra-efficient Ledsmentioning

confidence: 99%

“…According to Heikkila et al's model, 3 this would require that both IQE and C ex are approximately unity.…”

Section: Cooling In Airmentioning

confidence: 99%

“…[5][6][7][8][9] At the device level, Heikkila et al reported a detailed model of ultra-efficient LEDs concerning with carrier transport, recombination and photon extraction processes. 3 According to their numerical results, a GaAs LED might generate 1 W/cm 2 of cooling power. The thermoelectrical pumping effects in LEDs of various wavelength were also observed and reported by experimentalists.…”

Section: Previous Work On Ultra-efficient Ledsmentioning

confidence: 99%

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A design of a PhC-enhanced LED for electroluminescence cooling

Xue

Ram

2017

SPIE Proceedings

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Section: Previous Work On Ultra-efficient Ledsmentioning

confidence: 99%

“…According to Heikkila et al's model, 3 this would require that both IQE and C ex are approximately unity.…”

Section: Cooling In Airmentioning

confidence: 99%

Section: Previous Work On Ultra-efficient Ledsmentioning

confidence: 99%

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A design of a PhC-enhanced LED for electroluminescence cooling

Xue

Ram

2017

SPIE Proceedings

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“…[33]), using the time-dependent electron and hole densities from the MC simulation as inputs. In all the simulations, we use an SRH coefficient of 10 7 1 s −1 , a net radiative recombination coefficient of 4 × 10 −17 m 3 s −1 and an Auger coefficient of 10 −42 m 6 s −1 , similar to what was done in ref.…”

Section: Theorymentioning

confidence: 99%

On the Monte Carlo Description of Hot Carrier Effects and Device Characteristics of III‐N LEDs

Kivisaari

Sadi

et al. 2017

Adv Elect Materials

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of LED operation remain poorly understood, presenting an obvious bottleneck for further LED development and optimization. [5] For example, recent measurements have shown that III-N LEDs exhibit notable hot carrier distributions already close to the peak efficiency, [6][7][8][9] suggesting that hot carriers might have a more profound effect on the device characteristics than previously anticipated.To date, conventional LED simulations have mainly relied on the drift-diffusion (DD) model (see, e.g., refs. [10-13]), which cannot genuinely account for hot carriers and generally also produces larger turnon voltages for MQW LEDs than observed experimentally. [14] Many reasons have been suggested to explain this discrepancy, including charge transport through indium fluctuations, [15] V-shaped pits, [16] tunneling through traps [17] or hot carrier transport. [18] At present it is, however, unclear if the discrepancy is of a physical origin or if it arises simply because the very foundations of the widely adopted DD model make it incapable of predicting the most essential device-level characteristics of LEDs.The Monte Carlo (MC) method has been established as the standard tool to simulate hot-carrier effects in unipolar semiconductor devices such as transistors. Recently the MC method has also been expanded by Bertazzi et al. to simulate hot electron effects in GaN barriers of LEDs using full-band MC methods, [19] and ourselves, as we have recently developed a coupled Monte Carlo-drift-diffusion (MCDD) simulation method to investigate hot-electron effects in full III-N MQW LED structures. [20][21][22] More recently, we have also introduced a full MC model, [23] which can be used to carry out full MC simulations of both electrons and holes in a complete LED device. Nevertheless, the previous works have not yet provided a full analysis of the pertinent physics and differences between MC and DD. To provide more insight into the physics of MQW devices and to facilitate their further development, we now deploy our full MC simulator to answer the following questions:

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“…[1][2][3] Ideally, the high IQE is expected to enable electroluminescent (EL) cooling 4,5 if the high IQE can be converted to a high external quantum efficiency (EQE) by very efficient light extraction or by adopting thermophotonic (TPX) approaches where the light is absorbed within the semiconductor material. 6 While EL cooling at technologically relevant power levels is yet to be demonstrated, the expectations for functional thermophotonic coolers have very recently been reinforced by the progress and first demonstrations of optical refrigeration in doped glasses 7,8 and II-IV compound semiconductors 9 as well as the demonstrations of very low power EL cooling in GaSb/InGaAsSb LEDs.…”

Section: Yield and Leakage Currents Of Large Area Lattice Matched Inpmentioning

confidence: 99%

Yield and leakage currents of large area lattice matched InP/InGaAs heterostructures

Olsson¹,

Aierken²,

Jussila³

et al. 2014

Journal of Applied Physics

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Demonstrating and harnessing electroluminescent cooling at technologically viable cooling powers requires the ability to routinely fabricate large area high quality light-emitting diodes (LEDs). Detailed information on the performance and yield of relevant large area devices is not available, however. Here, we report extensive information on the yield and related large area scaling of InP/InGaAs LEDs and discuss the origin of the failure mechanisms based on lock-in thermographic imaging. The studied LEDs were fabricated as mesa structures of various sizes on epistructures grown at five different facilities specialized in the growth of III-V compound semiconductors. While the smaller mesas generally showed relatively good electrical characteristics and low leakage current densities, some of them also exhibited unusually large leakage current densities. The provided information is critical for the development and design of the optical cooling technologies relying on large area devices.

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Ultimate limit and temperature dependency of light-emitting diode efficiency

Cited by 71 publications

References 33 publications

A design of a PhC-enhanced LED for electroluminescence cooling

A design of a PhC-enhanced LED for electroluminescence cooling

On the Monte Carlo Description of Hot Carrier Effects and Device Characteristics of III‐N LEDs

Yield and leakage currents of large area lattice matched InP/InGaAs heterostructures

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