Effects of Nanosized Ni Particle Structure on the Enhancement of Light Extraction from 600 nm AlGaInP Light-Emitting Diodes

Lee, Hyung Joo; Castro, Edward Joseph D.; Kim, Jae-Hoon; Lee, Choong Hun

doi:10.1143/apex.5.122102

Cited by 9 publications

(4 citation statements)

References 35 publications

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“…The output power for NIR-LEDs can be increased by using multiple quantum wells (MQWs), window layers, distributed Bragg reflectors (DBRs), omnidirectional reflectors (ODRs), and current-spreading layers. MQWs are used to maximize the internal quantum efficiency of the active region in NIR-LEDs [ 5 ]. To improve the optical efficiency of NIR-LEDs with an absorbing substrate, a DBR must be used because it reflects the photons emitted from the active area in an upward direction [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

Improved Optical Efficiency of 850-nm Infrared Light-Emitting Diode with Reflective Transparent Structure

Lee¹,

Park

Kwac

et al. 2023

Micromachines

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This study investigated a reflective transparent structure to improve the optical efficiency of 850 nm infrared light-emitting diodes (IR-LEDs), by effectively enhancing the number of extracted photons emitted from the active region. The reflective transparent structure was fabricated by combining transparent epitaxial and reflective bonding structures. The transparent epitaxial structure was grown by the liquid-phase epitaxy method, which efficiently extracted photons emitted from the active area in IR-LEDs, both in the vertical and horizontal directions. Furthermore, a reflective bonding structure was fabricated using an omnidirectional reflector and a eutectic metal, which efficiently reflected the photons emitted downwards from the active area in an upward direction. To evaluate reflective transparent IR-LED efficiency, a conventional absorbing substrate infrared light-emitting diode (AS IR-LED) and a transparent substrate infrared light-emitting diode (TS IR-LED) were fabricated, and their characteristics were analyzed. Based on the power–current (L-I) evaluation results, the output power (212 mW) of the 850 nm IR-LED with the reflective transparent structure increased by 76% and 26%, relative to those of the AS IR-LED (121 mW) and TS IR-LED (169 mW), respectively. Furthermore, the reflective transparent structure possesses both transparent and reflective properties, as confirmed by photometric and radial theta measurements. Therefore, light photons emitted from the active area of the 850 nm IR-LED were efficiently extracted upward and sideways, because of the reflective transparent structure.

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Section: Introductionmentioning

confidence: 99%

Improved Optical Efficiency of 850-nm Infrared Light-Emitting Diode with Reflective Transparent Structure

Lee¹,

Park

Kwac

et al. 2023

Micromachines

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“…Extant studies have already indicated the relationship between light extraction efficiency and a few factors (such as textured structure and relative intermediate refractive index) significantly influence the output power of the light emitter. [16][17] Based on the hypothesis and experiment, the output power of the VCSEL was significantly increased by using the textured structure formed on both the top DBR and the anti-reflection film. Furthermore, the results verified that the obtained output power was further increased due to the relative intermediate refractive index of the anti-reflection film.…”

Section: Introductionmentioning

confidence: 96%

Optical extraction enhancement of an 860 nm GaAs based vertical-cavity surface emitting laser with a double textured structure

Lee¹,

Park²,

An³

et al. 2019

Jpn. J. Appl. Phys.

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The use of a double textured structure for improving the light extraction efficiency of an 860 nm GaAs vertical-cavity surface emitting laser (VCSEL) is investigated. The textured structure was formed on both surface of a GaP top layer and the surface of a SiN film used as an anti-reflection film. The measurement of the emission spectrum indicated that the light extraction efficiency of a VCSEL was increased by using it as a textured top surface as well as an anti-reflection film either without or with a textured surface. Significant increases in the light extraction efficiency were observed in the VCSEL with both a textured top structure and textured anti-reflection structure. The optical properties of VCSEL chips were used to obtain the highest output power of 127 mW with a double textured structure, which exhibits a relative increase of approximately 73% when compared to that of a conventional VSCEL (75 mW).

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“…To meet the demands of these applications, small NIR-LEDs that can deliver higher power outputs at large injection currents are required. For several years, multiple quantum wells (MQWs), distributed Bragg reflector (DBR), omni-directional reflector (ODR), and current spreading layers have been used to improve the output powers in NIR-LEDs [ 3 , 4 , 5 , 6 ]. However, the abrupt decrease in the surface-emitting area of these devices, due to a reduction in the chip size, was not investigated in prior research efforts [ 7 , 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Study on P-AlGaAs/Al/Au Ohmic Contact Characteristics for Improving Optoelectronic Response of Infrared Light-Emitting Device

Lee¹,

Shim

Park

et al. 2023

Micromachines

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The Al/Au alloy was investigated to improve the ohmic characteristic and light efficiency of reflective infrared light-emitting diodes (IR-LEDs). The Al/Au alloy, which was fabricated by combining 10% aluminum and 90% gold, led to considerably improved conductivity on the top layer of p-AlGaAs of the reflective IR-LEDs. In the wafer bond process required for fabricating the reflective IR-LED, the Al/Au alloy, which has filled the hole patterns in Si3N4 film, was used for improving the reflectivity of the Ag reflector and was bonded directly to the top layer of p-AlGaAs on the epitaxial wafer. Based on current-voltage measurements, it was found that the Al/Au alloyed material has a distinct ohmic characteristic pertaining to the p-AlGaAs layer compared with those of the Au/Be alloy material. Therefore, the Al/Au alloy may constitute one of the favored approaches for overcoming the insulative reflective structures of reflective IR-LEDs. For a current density of 200 mA, a lower forward voltage (1.56 V) was observed from the wafer bond IR-LED chip made with the Al/Au alloy; this voltage was remarkably lower in value than that of the conventional chip made with the Au/Be metal (2.29 V). A higher output power (182 mW) was observed from the reflective IR-LEDs made with the Al/Au alloy, thus displaying an increase of 64% compared with those made with the Au/Be alloy (111 mW).

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Effects of Nanosized Ni Particle Structure on the Enhancement of Light Extraction from 600 nm AlGaInP Light-Emitting Diodes

Cited by 9 publications

References 35 publications

Improved Optical Efficiency of 850-nm Infrared Light-Emitting Diode with Reflective Transparent Structure

Improved Optical Efficiency of 850-nm Infrared Light-Emitting Diode with Reflective Transparent Structure

Optical extraction enhancement of an 860 nm GaAs based vertical-cavity surface emitting laser with a double textured structure

Study on P-AlGaAs/Al/Au Ohmic Contact Characteristics for Improving Optoelectronic Response of Infrared Light-Emitting Device

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