Abstract:AlGaInP-based metal-bonding light-emitting diodes (LEDs) with micro-and nanoscale textured surface were investigated. The device surface with microbowls and nanorods were formed by a chemical wet-etching and dry-etching technique for enhancing light-extraction purpose. The luminous intensity could be enhanced 65.8% under 20-mA current injection as compared with the plane surface LEDs. The maximum wall-plug efficiency was achieved 14.1% at 7.5-mA operation.
“…On the other hand, as shown in Fig. 5b, the LEE of the AlGaInP VI-LEDs with the n-AlGaInP nanopillars was enhanced significantly because the nanopillars can increase the critical angle and the probability of photons escaping from the semiconductor-to-air interface [16]. Fig.…”
The light output power of AlGaInP-based vertical-injection light-emitting diodes (VI-LEDs) can be enhanced significantly using n-AlGaInP nanopillars. n-AlGaInP nanopillars, ~200 nm in diameter, were produced using SiO2 nanopillars as an etching mask, which were fabricated from self-assembled tin-doped indium oxide (ITO)-based nanodots formed by the wet etching of as-deposited ITO films. The AlGaInP-based VI-LEDs with the n-AlGaInP nanopillars provided 25 % light output power enhancement compared to VI-LEDs with a surface-roughened n-AlGaInP because of the reduced total internal reflection by the nanopillars at the n-AlGaInP/air interface with a large refractive index difference of 1.9.
“…On the other hand, as shown in Fig. 5b, the LEE of the AlGaInP VI-LEDs with the n-AlGaInP nanopillars was enhanced significantly because the nanopillars can increase the critical angle and the probability of photons escaping from the semiconductor-to-air interface [16]. Fig.…”
The light output power of AlGaInP-based vertical-injection light-emitting diodes (VI-LEDs) can be enhanced significantly using n-AlGaInP nanopillars. n-AlGaInP nanopillars, ~200 nm in diameter, were produced using SiO2 nanopillars as an etching mask, which were fabricated from self-assembled tin-doped indium oxide (ITO)-based nanodots formed by the wet etching of as-deposited ITO films. The AlGaInP-based VI-LEDs with the n-AlGaInP nanopillars provided 25 % light output power enhancement compared to VI-LEDs with a surface-roughened n-AlGaInP because of the reduced total internal reflection by the nanopillars at the n-AlGaInP/air interface with a large refractive index difference of 1.9.
“…improve the overall brightness and performance of LEDs. Some studies have proposed advanced DBRs using air-hybrid, metal-hybrid, and embedded nanoporous structures [15][16][17]. A DBR has been proven to significantly improve the efficiency of LEDs, and its characteristics strongly depend on interactions among its component materials.…”
Section: Methodsmentioning
confidence: 99%
“…DBRs can enhance the efficiency of light extraction from LEDs by providing a mirror-like surface that reflects light back into the LED material, which can improve the overall brightness and performance of LEDs. Some studies have proposed advanced DBRs using air-hybrid, metal-hybrid, and embedded nanoporous structures [ 15 , 16 , 17 ]. A DBR has been proven to significantly improve the efficiency of LEDs, and its characteristics strongly depend on interactions among its component materials.…”
This study developed an advanced 850 nm centered distributed Bragg reflector (DBR) (broadband DBR) composed of nanomaterial-based multiple structures to improve the optical efficiency of an 850 nm near-infrared light-emitting diode (NIR-LED). A combined 850 nm centered broadband DBR was fabricated by growing an 800 nm centered ten-pair DBR on a 900 nm centered ten-pair DBR (denoted as a combined DBR). The combined DBR exhibited a slightly wider peak band than conventional DBRs. Furthermore, the peak band width of the combined DBR significantly increased upon using a reflective AlAs buffer layer that reduced the overlapped reflection. The output power (20.5 mW) of NIR-LED chips using the combined DBR with an AlAs buffer layer exceeded that of a conventional 850 nm centered DBR (14.5 mW) by more than 40%. Results indicated that combining the optical conditions of wavelengths and the AlAs buffer layer effectively strengthened the broadband effect of the DBR and increased the optical efficiency of the 850 nm NIR-LED.
“…AlGaInP-based LEDs with both micro-and nanostructuring were investigated by Lee et al [101]. Here, 'microbowl' features were fabricated using wet chemi-cal etching and ME-like features were fabricated using colloidal lithography and dry etching.…”
Section: Other Materials Systems and Methodsmentioning
Near- and sub-wavelength photonic structures are used by numerous organisms (e.g. insects, cephalopods, fish, birds) to create vivid and often dynamically-tunable colors, as well as create, manipulate, or capture light for vision, communication, crypsis, photosynthesis, and defense. This review introduces the physics of moth eye (ME)-like, biomimetic nanostructures and discusses their application to reduce optical losses and improve efficiency of various optoelectronic devices, including photodetectors, photovoltaics, imagers, and light emitting diodes. Light-matter interactions at structured and heterogeneous surfaces over different length scales are discussed, as are the various methods used to create ME-inspired surfaces. Special interest is placed on a simple, scalable, and tunable method, namely colloidal lithography with plasma dry etching, to fabricate ME-inspired nanostructures in a vast suite of materials. Anti-reflective surfaces and coatings for IR devices and enhancing light extraction from visible light emitting diodes are highlighted.
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