Article
Materials Science, Multidisciplinary
Hajime Sakakita, Naoto Kumagai, Tetsuji Shimizu, Jaeho Kim, Hisashi Yamada, Xue-Lun Wang
Summary: In this study, high-quality bulk InN material was achieved through epitaxial growth on a GaN template, resulting in the lowest dislocation density reported to date and a narrow room-temperature full-width-at-half-maximum of the photoluminescence peak. This was made possible by a newly developed method combining microstrip-line microwave plasma irradiation with metal organic chemical vapor deposition, providing a standard guideline for non-toxic, low-energy-consumption, and low-cost manufacturing of numerous nitride-compound semiconductors.
APPLIED MATERIALS TODAY
(2022)
Article
Physics, Condensed Matter
Carsten Netzel, Arne Knauer, Frank Brunner, Anna Mogilatenko, Markus Weyers
Summary: Threading dislocations in c-plane (Al,Ga)N layers are surrounded by dark spots which reduce light generation efficiency. The diameter of dark spots is observed to vary with temperature in AlGaN and GaN, with different effects on emission energy mapping. Charge carrier localization and temperature-dependent excitation volume are dominant in AlGaN, while charge carrier diffusion limited by phonon scattering plays a key role in GaN.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Takaaki Mano, Akihiro Ohtake, Takuya Kawazu, Hideki T. Miyazaki, Yoshiki Sakuma
Summary: We demonstrate an extended short-wave infrared (e-SWIR) photodetector with interface misfit dislocations in an InAs/GaAs(111)A heterostructure. The photodetector consists of an n-InAs absorption layer directly grown on n-GaAs with a thin undoped-GaAs spacer layer. The formation of a misfit dislocation network in the InAs growth stage helps relax the lattice mismatch and suppress dark current, leading to efficient e-SWIR detection.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Optics
Chuankang Li, Yuzhu Li, Zhengyi Zhan, Yuhang Li, Xin Liu, Yong Liu, Xiang Hao, Cuifang Kuang, Xu Liu
Summary: Single molecular localization microscopy (SMLM) is a useful tool in biological observation with sub-10-nm resolution, but unable to distinguish two molecules within the diffraction-limited region without the help of a stochastic on-off switching scheme. SDLM introduces the concept of sub-diffraction dark spot (SDS) to overcome this limitation, allowing multiple molecules within the diffraction-limited region to be distinguished without the need for stochastic fluorescent switches.
PHOTONICS RESEARCH
(2021)
Article
Physics, Multidisciplinary
Kai-Heng Shao, Yu-Min Zhang, Jian-Feng Wang, Ke Xu
Summary: The dislocation slip behaviors in GaN bulk crystal were investigated by nanoindentation, observing the dislocation distribution patterns formed around an impress using cathodoluminescence (CL) and cross-sectional transmission electron microscope (TEM). Dislocation loops, vacancy luminescence, and cross-slips showed hexagonal symmetry around the 11-20 and 1-100 directions on the c-plane, with slip planes dominated in {0001} basal plane and {10-11} pyramid plane. Discussions on the dislocation formation process and related mechanisms were based on the dislocation intersection theory.
Article
Physics, Applied
Nadezda Varkentina, Yves Auad, Steffi Y. Woo, Florian Castioni, Jean-Denis Blazit, Marcel Tence, Huan-Cheng Chang, Jeson Chen, Kenji Watanabe, Takashi Taniguchi, Mathieu Kociak, Luiz H. G. Tizei
Summary: Electron-photon temporal correlations in electron energy loss spectroscopy and cathodoluminescence spectroscopy have been used to measure the relative quantum efficiency of materials. It has been found that cathodoluminescence excitation spectroscopy can also be used to measure the decay time of excitations and explore the energy dependence of decay time. By using well-known insulating materials, nanodiamonds with NV0 defects and hexagonal boron nitride with 4.1 eV defects, the instrumental response function has been characterized, and the measured lifetimes of the defects match previous reports.
APPLIED PHYSICS LETTERS
(2023)
Article
Crystallography
Youhua Zhu, Tao Hu, Meiyu Wang, Yi Li, Mei Ge, Xinglong Guo, Honghai Deng, Zhitao Chen
Summary: InAlN/GaN heterostructures were successfully grown on GaN/sapphire and AlN/sapphire substrates using metal organic chemical vapor deposition. The epitaxial quality was confirmed by X-ray diffraction, and transmission electron microscopy characterized micro-structural propagation defects originating from extended threading dislocations in the GaN layer. Cathodoluminescence peak shifting was observed with increasing acceleration voltage, attributed to factors such as inhomogeneous composition and internal absorption. Optimization of the structural parameters of the epilayers is expected to improve epitaxial quality and optoelectronic device design.
Article
Materials Science, Multidisciplinary
V. Orlov, A. Y. Polyakov, P. S. Vergeles, E. B. Yakimov, Gyu Cheol Kim, In-Hwan Lee
Summary: The study found that star-of-David-like rosettes can form in p-GaN even at room temperature, while in n-GaN, they require temperatures exceeding 573K. The activation energy for dislocation glide in p-GaN is lower than in n-GaN, resulting in a decrease in peak intensities in dislocated regions.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Applied
B. Ding, J. Jarman, M. J. Kappers, R. A. Oliver
Summary: By using STEM analysis, it was found that InGaN samples grown at lower temperatures exhibit microscale variations in the green-emitting surface, with brighter regions showing high density of gross-well width fluctuations, while dimmer regions have a more uniform thickness of InGaN QWs.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Applied
Ling Chen, Shanshan Sheng, Bowen Sheng, Tao Wang, Liuyun Yang, Baoqing Zhang, Jiajia Yang, Xiantong Zheng, Zhaoying Chen, Ping Wang, Weikun Ge, Bo Shen, Xinqiang Wang
Summary: We demonstrate a high electron mobility of similar to 4850 cm(2) V(-1)s(-1) in nearly-dislocation-free hexagonal InN at room temperature using Hall-effect measurement. These high-quality InN crystals were achieved through droplet-assisted epitaxy on a GaN/sapphire template by molecular beam epitaxy. The achievement of such high-mobility InN opens up promising opportunities for the fabrication of high-speed electronic devices.
APPLIED PHYSICS EXPRESS
(2022)
Article
Chemistry, Physical
Z. Benzarti, T. Sekrafi, A. Khalfallah, Z. Bougrioua, D. Vignaud, M. Evaristo, A. Cavaleiro
Summary: A series of N-polar InN epilayers were grown at various temperatures using plasma-assisted molecular beam epitaxy on GaN/AlN/Al2O3(0001) templates. Different island distributions and shapes were observed at varying growth temperatures, but the samples were identified as single crystalline phase regardless of temperature. Increasing the growth temperature up to 560 degrees C improved the crystalline quality, while excessively high temperatures led to degradation of quality.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Ceramics
Yang Yingkang, Shao Yiqing, Li Bailiang, Lu Zhiwei, Wang Lulu, Wang Liangjun, Cao Xun, Wu Yuning, Huang Rong, Yang Chang
Summary: In this study, Cl-doped CuI film was prepared by gas-phase reaction method, and the effects of Cl doping on the surface morphology and cathodoluminescence property of CuI films were investigated in detail. The main defects of Cl in CuI films were explored by combining first-principle calculations, revealing the relationship between structure and luminescent property of Cl-doped CuI films.
JOURNAL OF INORGANIC MATERIALS
(2023)
Article
Humanities, Multidisciplinary
E. Palamara, P. P. Das, S. Nicolopoulos, L. Tormo Cifuentes, E. Kouloumpi, A. Terlixi, N. Zacharias
Summary: This paper presents the characterization of common white pigments through SEM/CL method, aiming at identifying pigments through characteristic spectral analysis. The study found that even under different weathering conditions and with the influence of binding media, the characteristic spectra of pigments remain stable with distinct bands, facilitating accurate identification.
Article
Chemistry, Multidisciplinary
Pierre Lottigier, Davide Maria Di Paola, Duncan T. L. Alexander, Thomas F. K. Weatherley, Pablo Saenz de Santa Maria Modrono, Danxuan Chen, Gwenole Jacopin, Jean-Francois Carlin, Raphael Butte, Nicolas Grandjean
Summary: By inserting an In-containing underlayer during the growth of InGaN quantum wells (QWs) on thin GaN buffer layers, the emission efficiency of the QWs on silicon substrates is significantly increased. This study also reveals the crucial role of point defects in limiting the efficiency of InGaN QWs, even with a lower density compared to threading dislocations.
Article
Optics
Chuankang Li, Yuzhu Li, Yuhang Li, Xin Liu, Zhengyi Zhan, Xiang Hao, Cuifang Kuang, Xu Liu
Summary: This study investigates a novel beam pattern generated by laser beams with two distinct wavelengths, applied in fluorescence super resolution imaging. The results show that the resulting dark spot size in the focal plane is below the diffraction limit. Crucial factors affecting the sub-diffraction dark spot are thoroughly studied.
OPTICS COMMUNICATIONS
(2021)
