Determination of junction temperature in AlGaInP∕GaAs light emitting diodes by self-excited photoluminescence signal

Chen, N. C.; Wang, Y. N.; Tseng, C. Y.; Yang, Y. K.

doi:10.1063/1.2345587

Cited by 41 publications

(17 citation statements)

References 19 publications

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“…The band A (B) shifts toward higher (lower) energies when J is increased; the peak photon energies of band A are 1.406, 1.4065, and 1.414 eV, whereas those of band B are 1.365, 1.360, and 1.351 eV, at J = 22, 55, and 110 A/cm 2 , respectively. Using the observed blue and red shifts at J = 110 A/cm 2 , electron density and the temperature in the p-GaAs active layer are estimated to be ∼6 × 10 17 cm −3 and ∼319 K, respectively (44). Note that this electron density is around ∼1/5 of the threshold density for CP lasing that has been estimated by the optical pumping experiments using the vertical-cavity surface-emitting laser incorporating a bulk, undoped GaAs active layer (d = 485 nm) (24).…”

Section: Significancementioning

confidence: 99%

Pure circular polarization electroluminescence at room temperature with spin-polarized light-emitting diodes

Nishizawa

Nishibayashi

Munekata

2017

Proc. Natl. Acad. Sci. U.S.A.

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We report the room-temperature electroluminescence (EL) with nearly pure circular polarization (CP) from GaAs-based spinpolarized light-emitting diodes (spin-LEDs). External magnetic fields are not used during device operation. There are two small schemes in the tested spin-LEDs: first, the stripe-laser-like structure that helps intensify the EL light at the cleaved side walls below the spin injector Fe slab, and second, the crystalline AlO x spin-tunnel barrier that ensures electrically stable device operation. The purity of CP is depressively low in the low current density (J) region, whereas it increases steeply and reaches close to the pure CP when J > 100 A/cm 2 . There, either right-or left-handed CP component is significantly suppressed depending on the direction of magnetization of the spin injector. Spin-dependent reabsorption, spin-induced birefringence, and optical spin-axis conversion are suggested to account for the observed experimental results.A s well represented by the giant magnetoresistance, tunneling magnetoresistance, and spin-transfer-torque magnetic random access memory, spintronics research based on spin transport in magnetic metals has been contributing significantly in the progress of electronics through the advancement in recording bit density and low-power memory retention (1, 2). Proposal of the spin-current modulation with an electric field (3) and invention of diluted magnetic III-V semiconductors (4) have opened the opportunity of introducing spin degree of freedom in semiconductor technology (5). After those works, light-induced magnetism (6), electric-field-controlled magnetism (7), spin qubits in semiconductors (8, 9), spin-polarized light-emitting diodes (spinLEDs) (10, 11), and spin-metal-oxide-semiconductor field-effect transistor (12) were either demonstrated or proposed, which have caused an impact on the metal-based spintronics and applied physics that is not small. However, works that assure the roomtemperature (RT) operation of those semiconductor-based devices have not been accomplished to date.Concerning spin-LEDs, studies on a spin injector consisting of a ferromagnetic metal (FmM) and a tunnel barrier (TB) (13-15) succeeded those using semiconductor-based spin injectors (10, 11). The idea of the FmM-TB injector is to take advantage of spin-polarized carriers at RT with FmM and to simultaneously suppress with the TB the backward flow of unpolarized carriers that is unavoidable in the diffusive transport (16, 17). Many works have been carried out with the FmM-TB injector since then. Among those, the highest circular polarization (CP) value,) and I(σ − ) the intensity of right-and left-handed EL component, respectively, was P CP ∼ 0.3 ∼ 0.35 at RT in the external magnetic flux of B = 0.8 T, which was achieved in the context of studying the spinfiltering effect of the MgO TB (18,19). Most of the past works regarding spin-LED were carried out under the vertical arrangement with low J ranging from 0.1 to 1 A/cm 2 and forcing spins aligned vertically by applying out-of-pla...

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Section: Significancementioning

confidence: 99%

Pure circular polarization electroluminescence at room temperature with spin-polarized light-emitting diodes

Nishizawa

Nishibayashi

Munekata

2017

Proc. Natl. Acad. Sci. U.S.A.

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“…The wavelength shift is caused by the residual increase in temperature associated with the increase in dissipated power with increasing bias current [13,14].…”

Section: Spectral Distributionmentioning

confidence: 99%

Spectral Radiation Drift of LEDs Under Step-Mode Operation and Its Effect on the Measurement of the Non-Linearity of Radiation Thermometers

Wei

Yuan²,

Bloembergen³

et al. 2011

Int J Thermophys

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The non-linearity (NL) of radiation thermometers is critically involved when realizing ITS-90 above the silver point. It has to be corrected for, and its uncertainty should be adequately specified. In this article, results are presented of NL measurements based upon the superposition method and involving light emitting diodes (LEDs) with high radiance output, peaked at a wavelength of 645 nm. To this end, the two LEDs in question have been operated in the pulse mode with a fixed phase shift. Their spectral radiances have been measured by the radiation thermometers to be tested, separately or superimposed by means of a beam splitter. Still the drift in the spectral radiance observed after switching on the LEDs has to be taken into account and corrected for, since this drift, interfering during the superposition procedure, could corrupt the sum rule for the fluxes involved, which is the crux of the superposition method. Therefore, experimental research has been carried out to characterize the drift of LEDs operated in the pulse mode with a fixed phase shift. The result indicated that the drift could be roughly specified in terms of characteristic time intervals: non-linear drift in the first tens of seconds followed by a quasi-linear drift in the subsequent time interval. The crossover time from non-linear to quasi-linear drift could be ascertained by experiment. In the course of the superposition process, switching of the LEDs was done in such a way that only the quasi-linear part of the drift was involved which allowed for the correction of the drift in the NL measurements, as will be reported. Two radiation thermometers were involved in the NL measurements at radiance temperatures between the silver point and 3153 K: an LP-4, with a central wavelength 123 2588 Int J Thermophys (2011) 32:2587-2599 of 650 nm and 10 nm bandwidth, manufactured by KE-Technologie and the primary standard pyrometer PSP, with a central wavelength of 660 nm and 10 nm bandwidth, developed by NIM.

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“…[19][20][21][22][23][24] The temperature coefficient of the operating voltage should be obtained first. Figure 2 shows the currentvoltage (I-V) curves of the device under various temperatures.…”

Section: Junction Temperature Measurementmentioning

confidence: 99%

Measurement of Junction Temperature in a Nitride Light-Emitting Diode

Chen

Lin

Yang

et al. 2008

jjap

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The steady junction temperatures of a nitride light-emitting diode (LED) under various currents were measured. The measurements revealed a thermal resistance of R T ¼ 63:47 K/W. These data were further used to determine the evolution of the junction temperature with time. The transients of the junction temperature after the device was turned on were found to be described effectively on the basis of the theoretical curves. The thermal conductivity of the substrate was deduced and found to be higher for two reasons. The first is related to the optical power carried by photons. The second involves the difference between the p-mesa area and the chip area, which is a unique characteristic of nitride LEDs grown on insulating substrates.

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Determination of junction temperature in AlGaInP∕GaAs light emitting diodes by self-excited photoluminescence signal

Cited by 41 publications

References 19 publications

Pure circular polarization electroluminescence at room temperature with spin-polarized light-emitting diodes

Pure circular polarization electroluminescence at room temperature with spin-polarized light-emitting diodes

Spectral Radiation Drift of LEDs Under Step-Mode Operation and Its Effect on the Measurement of the Non-Linearity of Radiation Thermometers

Measurement of Junction Temperature in a Nitride Light-Emitting Diode

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