LED revolution: fundamentals and prospects for UV disinfection applications

Chen, Jian; Loeb, Stephanie; Kim, Jae Hong

doi:10.1039/c6ew00241b

Cited by 230 publications

(142 citation statements)

References 106 publications

Supporting

Mentioning

133

Contrasting

Unclassified

Order By: Relevance

“…UV LEDs are well suited for point-of-use (POU) devices since LEDs are smaller, lighter, less fragile, and mercury-free [12]. Moreover, UV LEDs offer the flexibility to use preferred germicidal wavelengths, which range from 254-280 nm (i.e., germicidal ultraviolet (UV-C)) [13][14][15][16][17][18][19]. Extensive studies have been conducted on microorganism inactivation using UV-C LEDs [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Efficacy of Inactivation of Human Enteroviruses by Dual-Wavelength Germicidal Ultraviolet (UV-C) Light Emitting Diodes (LEDs)

Woo

Beck

Boczek

et al. 2019

Water

View full text Add to dashboard Cite

The efficacy of germicidal ultraviolet (UV-C) light emitting diodes (LEDs) was evaluated for inactivating human enteroviruses included on the United States Environmental Protection Agency (EPA)’s Contaminant Candidate List (CCL). A UV-C LED device, emitting at peaks of 260 nm and 280 nm and the combination of 260/280 nm together, was used to measure and compare potential synergistic effects of dual wavelengths for disinfecting viral organisms. The 260 nm LED proved to be the most effective at inactivating the CCL enteroviruses tested. To obtain 2-log10 inactivation credit for the 260 nm LED, the fluences (UV doses) required are approximately 8 mJ/cm2 for coxsackievirus A10 and poliovirus 1, 10 mJ/cm2 for enterovirus 70, and 13 mJ/cm2 for echovirus 30. No synergistic effect was detected when evaluating the log inactivation of enteroviruses irradiated by the dual-wavelength UV-C LEDs.

show abstract

Section: Introductionmentioning

confidence: 99%

Efficacy of Inactivation of Human Enteroviruses by Dual-Wavelength Germicidal Ultraviolet (UV-C) Light Emitting Diodes (LEDs)

Woo

Beck

Boczek

et al. 2019

Water

View full text Add to dashboard Cite

show abstract

“…GaN, a wide bandgap semiconductor, has been extensively studied for a variety of applications such as power amplifiers, power conversion devices, and light-emitting diodes (LEDs) because of its large bandgap, high electron mobility, high electron velocity, high breakdown voltage, and the capability of forming various alloys. [1][2][3][4][5] GaN is a polar material with a wurtzite crystal structure, which results in a large polarization field along the c-axis of the crystal 6,7 which is the traditional direction of the GaN crystal growth. The polarization field has been used for polarization doping of heterostructures that show high electron mobilities.…”

Section: Introductionmentioning

confidence: 99%

Interface characterization of atomic layer deposited high-k on non-polar GaN

Jia

Zeng

Singisetti

2017

Journal of Applied Physics

View full text Add to dashboard Cite

The interface properties between dielectrics and semiconductors are crucial for electronic devices. In this work, we report the electrical characterization of the interface properties between atomic layer deposited Al2O3 and HfO2 on non-polar a-plane (112¯0) and m-plane (11¯00) GaN grown by hybrid vapor phase epitaxy. A metal oxide semiconductor capacitor (MOSCAP) structure was used to evaluate the interface properties. The impact of annealing on the interface properties was also investigated. The border trap in the oxide, characterized by the capacitance-voltage (C-V) hysteresis loop, was low. The interface state density (Dit), extracted using the ac conductance method, is in the range of 0.5 × 1012/cm2 eV to 7.5 × 1011/cm2 eV within an energy range from 0.2 eV to 0.5 eV below the conduction band minimum. The m-plane GaN MOSCAPs exhibited better interface properties than the a-plane GaN MOSCAPs after annealing. Without annealing, Al2O3 dielectrics had higher border trap density and interface state density compared to HfO2 dielectrics. However, the annealing had different impacts on Al2O3 dielectrics as compared to HfO2. Our results showed that the annealing degraded the quality of the interface in HfO2, but it improved the quality of the interface in Al2O3 devices. The annealing also reduced the positive trapped oxide charge, resulting in a shift of C-V curves towards the positive bias region.

show abstract

“…where is the material density in g/cm 3 In view of these results, and accounting for a reduction of the effective material density in the nanowire ensemble with respect to bulk material, the length of our quantum dot superlattices was chosen to be 400 nm. To maximize the number of emitting centres, the nominal superlattice period was fixed at 4.5 nm, which means that the active region consists of 88 quantum dot periods.…”

Section: Designmentioning

confidence: 99%

Assessment of AlGaN/AlN superlattices on GaN nanowires as active region of electron-pumped ultraviolet sources

Dimkou¹,

Harikumar²,

Donatini³

et al. 2020

Nanotechnology

View full text Add to dashboard Cite

In this paper, we describe the design and characterization of 400-nm-long (88 periods) AlxGa1-xN/AlN (0 ≤ x ≤ 0.1) quantum dot superlattices deposited on self-assembled GaN nanowires for application in electron-pumped ultraviolet sources. The optical performance of GaN/AlN superlattices on nanowires is compared with the emission of planar GaN/AlN superlattices with the same periodicity and thickness grown on bulk GaN substrates along the N-polar and metal-polar crystallographic axes. The nanowire samples are less sensitive to nonradiative recombination than planar layers, attaining internal quantum efficiencies (IQE) in excess of 60% at room temperature even under low injection conditions. The IQE remains stable for higher excitation power densities, up to 50 kW/cm 2 . We demonstrate that the nanowire superlattice is long enough to collect the electron-hole pairs generated by an electron beam with an acceleration voltage VA = 5 kV.At such VA, the light emitted from the nanowire ensemble does not show any sign of quenching under constant electron beam excitation (tested for an excitation power density around 8 kW/cm 2 over the scale of minutes). Varying the dot/barrier thickness ratio and the Al content in the dots, the nanowire peak emission can be tuned in the range from 340 to 258 nm.

show abstract

LED revolution: fundamentals and prospects for UV disinfection applications

Abstract: This review provides the fundamental and essential knowledge of UV-LEDs to better apply LED technology in environmental application.

Cited by 230 publications

References 106 publications

Efficacy of Inactivation of Human Enteroviruses by Dual-Wavelength Germicidal Ultraviolet (UV-C) Light Emitting Diodes (LEDs)

Efficacy of Inactivation of Human Enteroviruses by Dual-Wavelength Germicidal Ultraviolet (UV-C) Light Emitting Diodes (LEDs)

Interface characterization of atomic layer deposited high-k on non-polar GaN

Assessment of AlGaN/AlN superlattices on GaN nanowires as active region of electron-pumped ultraviolet sources

Contact Info

Product

Resources

About