Modestos AthanasiouUniversity of Cyprus · Department of Physics
Modestos Athanasiou
Beng in Electrical and Electronic Engineering,PhD III-Nitrides Optoelectronics
About
37
Publications
4,688
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305
Citations
Citations since 2017
Introduction
Additional affiliations
January 2020 - present
Position
- Fellow
Description
- PeroGaN project aims to produce novel light emitters for solid state and LiFi applications.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement.
January 2019 - December 2019
Position
- Fellow
Description
- Hybrid optoelectronics of III-nitrides and Perovskites NCs
December 2014 - January 2018
Position
- Research Associate
Description
- Semiconductor optoelectronics, specialized in III-nitrides nanofabrication and photonics
Publications
Publications (37)
Lead halide perovskite nanocrystals (NCs) are highly suitable active media for solution-processed lasers in the visible spectrum, owing to the wide tunability of their emission from blue to red via facile ion-exchange reactions. Their outstanding optical gain properties and the suppressed nonradiative recombination losses stem from their defect-tol...
Nanocrystal (NC) self-assembly is a versatile platform for materials engineering at the mesoscale. The NC shape anisotropy leads to structures not observed with spherical NCs. This work presents a broad structural diversity in multicomponent, long-range ordered superlattices (SLs) comprising highly luminescent cubic CsPbBr3 NCs (and FAPbBr3 NCs) co...
Electroluminescence polarization measurements have been performed on a series of semi-polar InGaN light emitting diodes (LEDs) grown on semi-polar (11–22) templates with a high crystal quality. The emission wavelengths of these LEDs cover a wide spectral region from 443 to 555 nm. A systematic study has been carried out in order to investigate the...
Down-conversion of light via phosphors is central to the generation of white and multi-color emission for solid-state lighting. Lead halide perovskite nanocrystals (NCs) are viable contenders to phosphors as they offer higher emission yields with narrower linewidth and facile synthesis and compositional tunability across the visible. Herein, we emp...
Carrier transport issues in a (11–22) semi-polar GaN based white light emitting diode (consisting of yellow and blue emissions) have been investigated by detailed simulations, demonstrating that the growth order of yellow and blue InGaN quantum wells plays a critically important role in achieving white emission. The growth order needs to be yellow...
An optically pumped multi-color laser has been achieved using an InGaN/GaN based micro-disk with an undercut structure on a silicon substrate. The micro-disk laser has been fabricated by means of a combination of a cost-effective microsphere lithography technique and subsequent dry/wet etching processes. The microdisk laser is approximately 1 μm in...
An electrically injected hybrid organic/inorganic III-nitride white light-emitting diode (LED) is presented with an architecture compatible with near-field requirements of highly-efficient non-radiative Förster resonance energy transfer (FRET) process. Time resolved photo-luminescence (TRPL) measurements confirm the non-radiative FRET process occur...
Microcavities based on group-III nitride material offer a notable platform for the investigation of light-matter interactions as well as the development of devices such as high efficiency light emitting diodes (LEDs) and low-threshold nanolasers. Disk or tube geometries in particular are attractive for low-threshold lasing applications due to their...
Highly polarised white light emission from a hybrid organic/inorganic device has been achieved. The hybrid devices are fabricated by means of combining blue InGaN-based multiple quantum wells (MQWs) with a one-dimensional (1D) grating structure and down-conversion F8BT yellow light emitting polymer. The 1D grating structure converts the blue emissi...
III-Nitride vertical-cavity surface-emitting lasers are challenging to achieve due to the difficulties involving incorporation of mirrors [1,2]. Whispering gallery mode laser has been suggested to overcome this challenge. Low-threshold laser in InGaN/GaN nanoring has been demonstrated on single nanoring with a diameter of 950 nm and a width of 80 n...
By means of a cost-effective approach, we demonstrate a GaN-based photoelectrode decorated with self-organized silver nano-islands employed for solar powered hydrogen generation, demonstrating 4 times increase in photocurrent compared with a reference sample without using any silver. Our photoelectrode exhibits a 60% incident photon-to-electron con...
A systematic investigation of the utilization of indium-tin-oxide (ITO) as a current spreading layer (CSL) with and without a textured surface has been performed on InGaN-based solar cells, demonstrating a difference in the influence on the performance of the devices. It is found that employing an ITO CSL improves the conversion efficiency for devi...
By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11–22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal
(PhC)
structure. Such a PhC
structure demonstrates not only significantly increased emission intensity, but also an enhanced...
The effect of surface states has been investigated in hybrid organic/inorganic white light emitting structures that employ high efficiency, nearfield non-radiative energy transfer (NRET) coupling. The structures utilize blue emitting InGaN/GaN multiple quantum well
(MQW)
nanorod arrays to minimize the separation with a yellow emitting F8BT coating....
The effect of surface states has been investigated in hybrid organic/inorganic white light emitting
structures that employ high efficiency, nearfield non-radiative energy transfer (NRET) coupling.
The structures utilize blue emitting InGaN/GaN multiple quantum well (MQW) nanorod arrays to
minimize the separation with a yellow emitting F8BT coating....
By means of time-resolved photoluminescence (PL) and confocal PL measurements, temporally and spatially resolved optical properties have been investigated on a number of InxGa1-xN/GaN multiple-quantum-well (MQW) structures with a wide range of indium content alloys from 13% to 35% on (11 (2) over bar2) semi-polar GaN with high crystal quality, obta...
Optically pumped green lasing with an ultra low threshold has been achieved using an InGaN/GaN based micro-disk with an undercut structure on silicon substrates. The micro-disks with a diameter of around 1 μm were fabricated by means of a combination of a cost-effective silica micro-sphere approach, dry-etching and subsequent chemical etching. The...
A “coherent” nanocavity structure has been designed on two-dimensional well-ordered InGaN/GaN nanodisk arrays with an emission wavelength in the green spectral region, leading to a massive enhancement in resonance mode in the green spectra region. By means of a cost-effective nanosphere lithography technique, we have fabricated such a structure on...
We demonstrate InGaN/GaN multi-quantum-well solar cells with nanostructures operating at a wavelength of 520 nm. Nanostructures with a periodic nanorod or nanohole array are fabricated by means of modified nanosphere lithography. Under 1 sun air-mass 1.5 global spectrum illumination, a fill factor of 50 and an open circuit voltage of 1.9 V are achi...
By means of combining a very cost-effective lift-off process and a nanosphere lithography technique, we have fabricated two dimensional (2D) photonic crystal (PhC) structures on an InGaN/GaN multiple quantum well structure. Significant enhancement in photoluminescence (PL) intensity has been observed when the emission wavelength is within the photo...
Projects
Projects (2)
We aim to develop advanced fabrication processes for Gallium Nitride (GaN) and related materials (AlN and InN) for the 21st Century manufacturing industries.
The III-Nitrides are functional materials that underpin the emerging global solid state lighting and power electronics industries. But their properties enable far wider applications: sensing by photonic, electronic and piezoelectric effects and in non-linear optics. Many applications of these functions are enhanced, even enabled by creating three-dimensional nanostructures.
Therefore we aim to develop nanostructuring processes on a manufacturing scale to unlock the potential of these properties of the III-Nitride semiconductors in a range of innovative materials and devices.
