Surface-plasmon-enhanced deep-UV light emitting diodes based on AlGaN multi-quantum wells

Gao, Na; Huang, Kai; Li, Jinchai; Li, Shuping; Yang, Xu; Kang, Junyong

doi:10.1038/srep00816

Cited by 108 publications

(82 citation statements)

References 53 publications

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“…Huang et al demonstrated for the first time that the enhanced emission of DUV-LEDs coupled to LSPRs generated by Al nanoparticles prepared on quantum wells (QWs) [66,67]. Size-and density-controlled Al nanoparticles were fabricated by OAD (see Sect.…”

Section: Duv-ledsmentioning

confidence: 99%

Coupling of Deep-Ultraviolet Photons and Electrons

Saito

2015

Far- And Deep-Ultraviolet Spectroscopy

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Recent advances in deep-ultraviolet (DUV) spectroscopy and related technologies have targeted the observation of photon-electron coupling in widebandgap materials. The energy of a single photon of DUV light is high enough to excite an electron to the first or higher electronic levels of a material. This is the main drawback of DUV spectroscopy for soft materials since higher-order excitations are often followed by photodamage. At the same time, high photon energy can be an advantage from the viewpoint of energy conversion between photons and electrons in a wide-bandgap material. DUV spans a marginal range of wavelengths that can occur under atmospheric pressure in sunlight on Earth. Its high photon energy and availability are expected to lead to great applications in DUV photonics. As mentioned in the previous chapter, photons couple with free electrons in metals at the nanometer scale, exhibiting a localization and enhancement effect known as localized surface plasmon resonance (LSPR). LSPR has been exploited in many scientific and industrial fields, such as sensors, optical waveguides, high-sensitivity optical detection, and high-resolution microscopy (Willets and Van Duyne, Rev Phys Chem 58:267-97, 2007). In this chapter, I review some important aspects of DUV photons, mainly focusing on DUV-LSPR applications in, for example, photocatalysis, photovoltaic devices, and light-emitting diodes (LEDs), including enhancement mechanisms such as carrier generation, photoexcited lifetime modifications, emission pattern controls, and coulombic forces.Keywords Localized surface plasmon resonance • Plasmonic nanostructure • Photocatalysis • DUV-LED DUV Plasmonic NanostructuresFor efficient coupling between a photon wave vector and free electrons in a material, the specific shape and size of nanostructures, the so-called plasmonic nanostructures, should be prepared to host LSPR. In order to achieve LSPR in Y. Saito ( )

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Section: Duv-ledsmentioning

confidence: 99%

Coupling of Deep-Ultraviolet Photons and Electrons

Saito

2015

Far- And Deep-Ultraviolet Spectroscopy

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“…Recently, the LEE of NUV-LEDs is expected to be enhanced by the LSPs and TM-light coupling. At a LSPs-TM light resonance condition, it provides that metallic nanoparticles capture the trapped TM-light in p-GaN layer and transparent conductive layer of LED device and enhance the extracting efficiency of light [27,28]. In this case, the energy of the generated photons in the active layers is first transferred to the metallic nanoparticles to induce LSPs followed by emission of light.…”

Section: Introductionmentioning

confidence: 97%

Improved UV LED performance using transparent conductive films embedded with plasmonic structures

Chuang

Lin

et al. 2015

SPIE Proceedings

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Recently, near-ultraviolet light-emitting diodes (NUV-LEDs) have been used in many applications such as light sources for ultraviolet curing, environmental cleaning, biomedical instrumentation, counterfeit bill detection and phosphor-based white LEDs. However, it is difficult to fabricate NUV-LEDs with high emission efficiency. As the wavelength of NUVLEDs decreases, the most dominant emission will be photons with transverse-magnetic (TM) polarization. For LED structures grown on a c-plane substrate, TM-light propagates mainly in the lateral direction, and it suffers strong effects of total internal reflection (TIR) due to the large incident angle on the interface. Therefore, light extraction efficiency (LEE) of NUV-LEDs is still lower than that of visible LEDs. In this study, a spin coating process in which the grating structure comprises the metallic nanoparticle layer coated on a p-GaN top layer was developed. Various sizes of metallic nanoparticles forming a suspended nanoparticle layer (SNL) embedded in a transparent conductive layer were clearly observed after the deposition of indium tin oxide (ITO). The SNL enhanced the light extraction efficiency of NUVLEDs. Light output power was 1.4 times the magnitude of that of conventional NUV-LEDs operating at 350 mA, but retained nearly the same current-voltage characteristic. Unlike in previous research on surface-plasmon-enhanced LEDs, the metallic nanoparticles were consistently distributed over the surface area. Device performance can be improved substantially by using the three-dimensional distribution of metallic nanoparticles in the SNL, which scatters the propagating light randomly and is coupled between the localized surface plasmon and incident light internally trapped in the LED structure through TIR.Keywords: Surface plasmon, nanoparticle, light-emitting diode (LED), internal quantum efficiency (IQE), external quantum efficiency (EQE), light extraction efficiency (LEE), electroluminescence spectrum, metal-organic chemical vapor deposition (MOCVD), localized surface plasmons (LSPs), transparent conductive layer.

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“…Group III nitrides, such as AlN and AlGaN, have attracted great attention due to increasing demand for ultraviolet light sources used in various applications [1][2][3][4]. Low dislocation densities are needed to improve device performance, as dislocations usually act as nonradiative recombination centers [5].…”

Section: Introductionmentioning

confidence: 99%