Article
Physics, Applied
B. Damilano, S. Vezian, M. P. Chauvat, P. Ruterana, N. Amador-Mendez, S. Collin, M. Tchernycheva, P. Valvin, B. Gil
Summary: InGaN/GaN single quantum wells grown on silicon substrates with thin AlN and GaN buffer layers were made nanoporous using SixNy nanomasking and sublimation, leading to a significant improvement in photoluminescence efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Jin Zhang
Summary: In this paper, the piezopotential properties of graded InGaN nanowires were studied through multiscale modeling. The results show that the piezopotential in graded InGaN NWs is asymmetric to the NW center and can be enhanced by increasing the In composition.
Article
Nanoscience & Nanotechnology
Weifang Lu, Nanami Nakayama, Kazuma Ito, Sae Katsuro, Naoki Sone, Yoshiya Miyamoto, Koji Okuno, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu Akasaki
Summary: The morphology and crystalline quality of p-GaN shells on coaxial GaInN/GaN multiple quantum shell nanowires (NWs) were investigated, with the TMG supply and growth temperature found to be crucial parameters. High-angle annular dark-field scanning transmission electron microscopy characterization revealed no clear extended defects in the core and sidewall of the NWs, but some dislocations were observed at the interface between the serpentine MQS and the p-GaN shell near the tips.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Review
Physics, Applied
D. J. Binks, P. Dawson, R. A. Oliver, D. J. Wallis
Summary: LEDs based on hexagonal InGaN/GaN quantum wells are widely used for lighting applications, but their performance is limited for green and amber emission and at high drive currents. Growing quantum wells in the cubic phase is a promising alternative due to its reduced bandgap and absence of strong polarization fields. The major structural defects in cubic GaN are stacking faults, which affect the optical properties and can propagate into active layers.
APPLIED PHYSICS REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Julien Bosch, Pierre-Marie Coulon, Sebastien Chenot, Marc Portail, Christophe Durand, Maria Tchernycheva, Philip A. Shields, Jesus Zuniga-Perez, Blandine Alloing
Summary: This paper proposes three different strategies, chemical, physical, or thermal etching, to remove the SiGaxNy layer on the sidewalls of GaN core-shell wires, thereby improving their optical quality. Chemical etching with H3PO4 enhances the emissive coverage and luminescence intensity, while removing deep-defect emissions from the high growth temperature.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Computer Science, Information Systems
Anna Reszka, Krzysztof P. Korona, Stanislav Tiagulskyi, Henryk Turski, Uwe Jahn, Slawomir Kret, Rafal Bozek, Marta Sobanska, Zbigniew R. Zytkiewicz, Bogdan J. Kowalski
Summary: This study provides a comprehensive analysis of the morphological, electrical, and optical properties of GaN/AlGaN nanowire LEDs through nanoscale experiments and numerical simulations. It highlights the impact of nanowire polarity and the importance of polarity inversion on the optical and electrical performance.
Article
Physics, Applied
Zhiming Shi, Aiqin Tian, Xiaojuan Sun, Xuan Li, Hang Zang, Xujun Su, Hao Lin, Peng Xu, Hui Yang, Jianping Liu, Dabing Li
Summary: In this study, the atomic formation mechanism of trench defects in InGaN multiple quantum wells (MQWs) was revealed through thermodynamic analysis based on first-principles calculations and experimental confirmation. It was found that the In-rich region induces basal plane stacking faults (BSFs), resulting in low emission efficiency. The presence of trench defects originating from the thick GaN quantum barrier (QB) layer was observed, which had excess indium and poor crystal quality based on cathodoluminescence measurements.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Dezhong Cao, Hongdi Xiao, Xiaokun Yang, Xiaohua Ma
Summary: Researchers fabricated large-area and highly reflective MP-GaN DBRs for the first time via electrochemical etching technology, and found that the InGaN/GaN structure with MP-GaN DBRs exhibited significantly increased PL intensity and improved PEC properties during water splitting experiments.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Fedor M. Kochetkov, Vladimir Neplokh, Viktoria A. Mastalieva, Sungat Mukhangali, Aleksandr A. Vorob'ev, Aleksandr Uvarov, Filipp E. Komissarenko, Dmitry M. Mitin, Akanksha Kapoor, Joel Eymery, Nuno Amador-Mendez, Christophe Durand, Dmitry Krasnikov, Albert G. Nasibulin, Maria Tchernycheva, Ivan S. Mukhin
Summary: This study presents and demonstrates flexible and stretchable blue-light-emitting diodes based on core/shell InGaN/GaN quantum well microwires embedded in polydimethylsiloxane membranes with strain-insensitive transparent electrodes using single-walled carbon nanotube films. The fabricated free-standing membrane LEDs, which can be stretched up to 20%, show less than 15% degradation in electroluminescence intensity after 20 cycles of stretching, indicating potential for highly deformable inorganic devices.
Article
Chemistry, Multidisciplinary
Yan Gu, Yu Shen Liu, Guofeng Yang, Feng Xie, Chun Zhu, Yingzhou Yu, Xiumei Zhang, Naiyan Lu, Yueke Wang, Guoqing Chen
Summary: A nanostructure of In0.18Ga0.82N/GaN multiple quantum well nanorods was fabricated using top-down etching with self-organized nickel nanoparticles as masks. The optical properties of the nanorods were discussed from a light absorption perspective, with optical simulations performed to explore the influences of geometric parameters on absorption. Results showed higher absorption in the nanorods compared to the film, with an increase in diameter leading to a red-shift in absorption peak position.
NANOSCALE ADVANCES
(2021)
Article
Chemistry, Multidisciplinary
Liwen Cheng, Zhenwei Li, Jiayi Zhang, Xingyu Lin, Da Yang, Haitao Chen, Shudong Wu, Shun Yao
Summary: An InGaN laser diode with InGaN-GaN-InGaN delta barriers demonstrates lower turn-on current, higher laser power, and higher slope efficiency compared to those with InGaN or conventional GaN barriers. These improvements are attributed to modified energy bands that enhance carrier injection within the active region.
Article
Optics
Mirsaeid Sarollahi, Pijush K. Ghosh, Manal A. Aldawsari, Shiva Davari, Malak Refaei, Reem Alhelais, Yuriy Mazur, Morgan E. Ware
Summary: Graded InGaN structures were designed by increasing indium composition, forming a Zig-Zag quantum well with broadband emission shifting to lower energies. The lowest energy band-to-band transition shifts noticeably with higher indium content, making the structure useful in optoelectronic devices.
JOURNAL OF LUMINESCENCE
(2021)
Article
Physics, Applied
S. A. Church, M. Quinn, K. Cooley-Greene, B. Ding, A. Gundimeda, M. J. Kappers, M. Frentrup, D. J. Wallis, R. A. Oliver, D. J. Binks
Summary: Research indicates that growing InGaN/GaN quantum wells in the zincblende crystal phase has the potential to improve efficiency, with increasing the number and width of the quantum wells significantly enhancing emission efficiency.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Liliia Dvoretckaia, Vladislav Gridchin, Alexey Mozharov, Alina Maksimova, Anna Dragunova, Ivan Melnichenko, Dmitry Mitin, Alexandr Vinogradov, Ivan Mukhin, Georgy Cirlin
Summary: The direct integration of epitaxial III-V and III-N heterostructures on Si substrates provides a promising platform for the development of optoelectronic devices. This study presents the molecular beam epitaxy of ordered arrays of n-GaN/i-InGaN/p-GaN heterostructured nanowires and tripods on Si/SiO2 substrates using cost-effective and rapid microsphere optical lithography. The fabricated n-GaN/i-InGaN/p-GaN NWs-based LEDs exhibit electroluminescence in a broad spectral range, with a maximum near 500 nm, which can be utilized for the development of multicolor or white light screens.
Article
Nanoscience & Nanotechnology
Anthony Aiello, Debabrata Das, Pallab Bhattacharya
Summary: In this study, InGaN/GaN quantum dot light-emitting diodes were demonstrated on silicon substrates with a planar buffer layer formed by coalescing GaN nanowires. The devices showed strong electroluminescence with a minimal blue shift and a polarization field. However, efficiency droop was observed beyond an injection of 40A/cm(2), possibly due to defect-assisted Auger recombination and carrier leakage from the active region.
ACS APPLIED NANO MATERIALS
(2021)
Article
Physics, Applied
Ece N. Aybeke, Alexandra-Madalina Siladie, Remy Vermeersch, Eric Robin, Oleksandr Synhaivskyi, Bruno Gayral, Julien Pernot, Georges Bremond, Bruno Daudin
Summary: Practical semiconductor nanowire optoelectronic devices require controlling their electrical transport properties. This study quantitatively measured the local carrier density in doped GaN nanowires using scanning spreading resistance microscopy. The results reveal the presence of a conductive shell and resistive core in Mg-doped p-type nanowires, while Si-doped n-type nanowires exhibit a resistive shell and conductive core.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Optics
Zhaogang Dong, Zackaria Mahfoud, Ramon Paniagua-Dominguez, Hongtao Wang, Antonio I. Fernandez-Dominguez, Sergey Gorelik, Son Tung Ha, Febiana Tjiptoharsono, Arseniy I. Kuznetsov, Michel Bosman, Joel K. W. Yang
Summary: This paper presents the near-field localization of true bound-states-in-the-continuum (BIC) resonance on arrays of silicon nanoantennas using electron energy loss spectroscopy. By breaking the antenna symmetry, emissive quasi-BIC resonances are observed. It is also demonstrated that the quasi-BIC resonances can significantly enhance localized light emission via the Purcell effect.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Jose P. S. Cardoso, Maria Rosario Correia, Remy Vermeersch, Dirkjan Verheij, Gwenole Jacopin, Julien Pernot, Teresa Monteiro, Susana Cardoso, Katharina Lorenz, Bruno Daudin, Nabiha Ben Sedrine
Summary: Europium-implanted AlN nanowire pn junctions were annealed at 1000 degrees C and showed increased Eu3+ luminescence intensity with higher fluence, while the contribution from defect-related emissions decreased. This study demonstrates the potential of using Eu-implanted AlN NWs for developing red LEDs with improved luminescence properties.
ACS APPLIED NANO MATERIALS
(2022)
Article
Physics, Applied
Julien Bassaler, Remi Comyn, Catherine Bougerol, Yvon Cordier, Farid Medjdoub, Philippe Ferrandis
Summary: This study focuses on the material investigation of an Al0.9Ga0.1N/GaN heterostructure, identifying various defects in the GaN channel that may contribute to reduced mobility and are linked to the quality of the channel interfaces.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Optics
Quang Minh Thai, Sergi Cuesta, Lou Denaix, Sylvain Hermelin, Olivier Boisron, Edith Bellet-Amalric, Catherine Bougerol, Florian Castioni, Stephen T. Purcell, Le Si Dang, Eva Monroy
Summary: This study reports the net gain measurements of Al0.07Ga0.93N/GaN 10-period multi-quantum well layers emitting at 367 nm at room temperature using the variable stripe length method. The highest net gain value obtained was 131 cm(-1), and the net gain threshold was reached at 218 kW/cm(2). Additionally, the study identified an anomalous amplification of the photoluminescence intensity for long stripe lengths and high pumping power.
Article
Instruments & Instrumentation
Ricardo Javier Pena Roman, Yves Auad, Lucas Grasso, Lazaro A. Padilha, Fernando Alvarez, Ingrid David Barcelos, Mathieu Kociak, Luiz Fernando Zagonel
Summary: This paper presents a light collection/injection strategy based on an off-axis parabolic mirror collector for a low-temperature Scanning Tunneling Microscope (STM). The system allows for various spectroscopic techniques and demonstrates flexible and efficient light injection and collection capabilities on metallic surfaces and semiconducting samples.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Nanoscience & Nanotechnology
Alexandre Concordel, Joel Bleuse, Gwenole Jacopin, Bruno Daudin
Summary: The optical properties of nanowire-based InGaN/GaN multiple quantum wells (MQWs) heterostructures grown by plasma-assisted molecular beam epitaxy were investigated, with a focus on the effect of an InGaN underlayer grown below the active region and the influence of surface recombination. It was found that the InGaN underlayer demonstrated a beneficial effect due to the trapping of point defects transferred from the pseudo-template to the active region. Surface recombination was found to be dominated by the formation of additional point defects during the growth of the heterostructure for large InN molar fraction. Inhomogeneous luminescence of single nanowires at the nanoscale highlighted a spatial distribution of non-radiative recombination centers identified as intrinsic point defects created during the growth of MQWs. These findings have implications for improving the performance of microLEDs in the visible range.
Article
Chemistry, Multidisciplinary
Ricardo Javier Pena Roman, Remi Bretel, Delphine Pommier, Luis Enrique Parra Lopez, Etienne Lorchat, Elizabeth Boer-Duchemin, Gerald Dujardin, Andrei G. Borisov, Luiz Fernando Zagonel, Guillaume Schull, Stephane Berciaud, Eric Le Moal
Summary: This study demonstrates the local and electrical control of photoluminescence in monolayer WS2 using a nonplasmonic tip and tunneling current of a scanning tunneling microscope. The results show that short-range photoluminescence quenching is present due to near-field electromagnetic effects, independent of the bias voltage. Additionally, a bias-voltage-dependent long-range photoluminescence quenching is observed when the sample is positively biased.
Article
Physics, Applied
Remy Vermeersch, Gwenole Jacopin, Eric Robin, Julien Pernot, Bruno Gayral, Bruno Daudin
Summary: We have demonstrated that intentional Ga doping of AlN nanowires in the range of 0.01%-0.5% results in the formation of nanometric carrier localization centers. This leads to the observation of sharp cathodoluminescence lines in the wavelength range of 220-300 nm for single nanowires. Additionally, an ensemble of Ga-doped AlN nanowires exhibits wide-band cathodoluminescence emission, paving the way for efficient UV-C light emitting diodes covering a wide part of the DNA absorption band.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Reda Elwaradi, Jash Mehta, Thi Huong Ngo, Maud Nemoz, Catherine Bougerol, Farid Medjdoub, Yvon Cordier
Summary: In this study, two series of AlGaN/GaN/AlN high electron mobility transistor (HEMT) heterostructures were grown using molecular beam epitaxy. The effects of reducing the GaN channel thickness and varying the AlGaN barrier thickness and composition on the structural and electrical properties of the heterostructures were investigated. Material analysis techniques such as high-resolution x-ray diffraction, atomic force microscopy, and cross-sectional transmission electron microscopy were employed. The results showed that reducing the GaN channel thickness led to a decrease in GaN strain relaxation rate, but also caused degradation in crystal quality and electron mobility, along with an increase in sheet resistance. However, a trade-off was observed for a specific HEMT structure with a 50 nm width GaN channel, which exhibited a moderate sheet resistance and a high three-terminal breakdown voltage.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Fabio J. R. Costa, Thiago G-L Brito, Ingrid D. Barcelos, Luiz Fernando Zagonel
Summary: Single layers of transition metal dichalcogenides (TMDCs), such as WSe2, have attracted increasing attention for their intense electron-hole interactions and potential for novel optical applications. The dielectric properties of substrates significantly influence the electronic and optical properties of these atomically-thin semiconductors, including the band-gap and luminescence intensity. Increasing permittivity induces a red-shift of the optical band-gap and a reduction in luminescence intensity of WSe2.
Article
Nanoscience & Nanotechnology
Remy Vermeersch, Gwenole Jacopin, Florian Castioni, Jean-Luc Rouviere, Alberto Garcia-Cristobal, Ana Cros, Julien Pernot, Bruno Daudin
Summary: The growth and optical properties of GaN quantum disks in AlN nanowires were studied via molecular beam epitaxy to control the emission wavelength of AlN nanowire-based LEDs. In addition to GaN quantum disks with thickness ranging from 1 to 4 monolayers, focus was given to incomplete GaN disks with lateral confinement. Their emission spectrum consists of sharp lines extending down to 215 nm near the AlN band edge. The room temperature cathodoluminescence intensity of GaN quantum disks embedded in AlN nanowires is about 20% of the low temperature value, highlighting the potential of ultrathin/incomplete GaN quantum disks for deep UV emission.
Article
Nanoscience & Nanotechnology
Claudevan A. Sousa, Luiz G. Bonato, Eduardo S. Goncalves, Arthur Alo, Brener R. C. Vale, Diogo B. Almeida, Ana F. Nogueira, Luiz F. Zagonel, Lazaro A. Padilha
Summary: In this paper, the nonlinear optical response of CsPbBr3 perovskite nanocrystals was investigated and found to be not particularly high. The measured nonlinear refractive index was in the same order of magnitude as other semiconductors.
Article
Multidisciplinary Sciences
Yves Auad, Eduardo J. C. Dias, Marcel Tence, Jean-Denis Blazit, Xiaoyan Li, Luiz Fernando Zagonel, Odile Stephan, Luiz H. G. Tizei, F. Javier Garcia de Abajo, Mathieu Kociak
Summary: The authors propose a technique that combines free-space light and electron beams to achieve unmatched spatial and spectral resolution. This approach allows detailed investigation of photonic structures, promising advancements in microscopy and quantum optics.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Ricardo Javier Pena Roman, Delphine Pommier, Remi Bretel, Luis E. Parra Lopez, Etienne Lorchat, Julien Chaste, Abdelkarim Ouerghi, Severine Le Moal, Elizabeth Boer-Duchemin, Gerald Dujardin, Andrey G. Borisov, Luiz F. Zagonel, Guillaume Schull, Stephane Berciaud, Eric Le Moal
Summary: This study investigates the generation of excitons in monolayer WS2 using inelastic electron tunneling in a scanning tunneling microscope. Optical spectroscopy and Fourier-space optical microscopy reveal that the bias polarity of the tunnel junction determines the spectral and angular distribution of the emitted light.
