Article
Materials Science, Multidisciplinary
Le Chang, Zhilin Tao, Sisheng Yang, Xinran Liu, Changyu Zhou
Summary: Molecular dynamics simulation is used to investigate the tensile deformation of nanocrystalline titanium with different textures and grain sizes. The study reveals that the mechanical properties vary with different textures, with complex twinning-dislocation and dislocation-dislocation interactions being the main factors in [11(2)bar0] texture, and easier prismatic slip dominantly occurring in [0001]-textured samples. Plastic deformation in [10(1)bar0]-textured samples is mainly controlled by twinning. Grain boundary mediated plasticity is more pronounced in [10(1)bar0]-textured structures, while it is restricted by dislocation pile-ups in [11(2)bar0]-textured structures. The study also quantitatively analyzes the effects of grain size on twin variant number, twin fraction, and dislocation number.
RESULTS IN PHYSICS
(2022)
Article
Crystallography
Jianguo Zhao, Boyan Suo, Ru Xu, Tao Tao, Zhe Zhuang, Bin Liu, Xiong Zhang, Jianhua Chang
Summary: Nonpolar (11 (2) over bar0) a-plane GaN films were grown on semipolar (1 (1) over bar 02) r-plane sapphire substrates using various buffer layers. The structural properties of the films were investigated and it was found that using a composite buffer layer can effectively reduce the density of basal-plane stacking faults (BSFs) and achieve a pit-free surface morphology.
Article
Chemistry, Multidisciplinary
Marta Sawicka, Julita Smalc-Koziorowska, Marcin Krysko, Natalia Fiuczek, Pawel Wolny, Anna Feduniewicz-Zmuda, Krzesimir Nowakowski-Szkudlarek, Henryk Turski, Czeslaw Skierbiszewski
Summary: The study reports the indium incorporation efficiency and structural quality of nonpolar and semipolar InAIN layers grown by plasma-assisted molecular beam epitaxy. The indium content is found to depend on surface orientation, leading to different incorporation efficiencies for the different orientations. Additionally, one-dimensional strain relaxation is observed for the m-plane InAIN layer, while the semipolar and c-plane InAIN layers are strained to GaN.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Chemistry, Physical
Laima Trinkler, Ilze Aulika, Guna Krieke, Dace Nilova, Rihards Ruska, Jelena Butikova, Baiba Berzina, Mitch Ming-Chi Chou, Liuwen Chang, Meng-Chieh Wen, Tao Yan, Ramunas Nedzinskas
Summary: The properties and quality of Wurtzite Zn1-xMgxO epilayers grown by plasma-assisted molecular beam epitaxy on ScAlMgO4 substrate were studied using optical spectroscopy methods. The increase in band gap width with the rise of MgO content makes the epilayers a recommended material for UV sensors.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Ceramics
Ray-Hua Horng, Apoorva Sood, Fu-Gow Tarntair, Dong-Sing Wuu, Ching-Lien Hsiao, Singh Jitendra Pratap
Summary: In this study, the electrical properties of unintentionally doped (UID) 8-Ga2O3 epilayers were tuned using Si-ions implantation technique. The effects of different doses and dose energies on the electrical properties were examined and characterized using various techniques. Ion implantation was found to effectively reduce the resistivity and increase the carrier concentrations in the 8-Ga2O3 epilayers.
CERAMICS INTERNATIONAL
(2022)
Article
Physics, Applied
Abhiram Gundimeda, Martin Frentrup, Simon M. Fairclough, Menno J. Kappers, David J. Wallis, Rachel A. Oliver
Summary: The influence of AlGaN nucleation layers on zincblende GaN epilayers and the formation of wurtzite phase inclusions in the epilayer were studied. It was found that an increase in aluminum content in the AlGaN nucleation layer leads to an increased presence of wurtzite inclusions. The strong {111}-type faceting observed in the zincblende nucleation layer on an Al0.29Ga0.71N nucleation layer contributes to the formation of wurtzite inclusions at the GaN/ Al0.29Ga0.71N interface.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Zhiqiang Liu, Bingyao Liu, Fang Ren, Yue Yin, Shuo Zhang, Meng Liang, Zhipeng Dou, Zhetong Liu, Shenyuan Yang, Jianchang Yan, Tongbo Wei, Xiaoyan Yi, Chaoxing Wu, Tailiang Guo, Junxi Wang, Yong Zhang, Jinmin Li, Peng Gao
Summary: This study investigates the polarity determination and evolution mechanism of polar wurtzite nitrides on nonpolar substrates. The findings reveal a spontaneous polarity inversion during the growth and the formation of inherent inverse grain boundaries. Additionally, it identifies the occurrence of vertical two-dimensional electron accumulation originating from the lattice symmetry breaking at the inverse grain boundary.
Article
Chemistry, Physical
Yufeng Huang, Yaxu Wei, Yanning Li, Chunguang Hu, Wanfu Shen, Kun Zhang, Zongwei Xu, Lidong Sun
Summary: A singly oriented MoSe2 monolayer was grown on an Al2O3(11 (2) over bar0) substrate using molecular beam epitaxy (MBE). The growth process can be divided into small island growth and subsequent coalescence, with MoSe2 nuclei and domains preferentially aligning their zig-zag direction along the Al2O3[0001] direction due to the two-fold lattice symmetry of the substrate surface. The increase and decrease of optical anisotropy during island growth and coalescence, respectively, indicate the dominance of interfacial interaction with the substrate surface and the lateral interaction within the MoSe2 monolayer.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Apoorva Sood, Dong-Sing Wuu, Fu-Gow Tarntair, Ngo Thien Sao, Tian-Li Wu, Niall Tumilty, Hao-Chung Kuo, Singh Jitendra Pratap, Ray-Hua Horng
Summary: 13-Ga2O3 epilayers with a thickness of 210 nm were grown on c-plane sapphire substrate by MOCVD. The conductivity of the 13-Ga2O3 epilayer was improved by Si ion-implantation at doses of 1x1014, 6x1014, and 1x1015 cm-2. Schottky barrier diodes were fabricated and showed significant improvement in forward current density and breakdown voltage after Si implantation.
MATERIALS TODAY ADVANCES
(2023)
Article
Physics, Multidisciplinary
Seoung-Hwan Park, Jong-In Shim, Dong-Soo Shin
Summary: The in-plane polarization characteristics of nonpolar (11 (2) over bar0) InxGa1-xN/GaN (x = 0.2) quantum-well (QW) structures change as the In content in the InGaN substrate increases. The topmost valence subband shifts from Y' >-like to Z' >-like states. The in-plane optical anisotropy becomes smaller for QW structures with higher substrate In content because both x'- and y' -polarized emission peaks are similar to each other.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Ray-Hua Horng, Apoorva Sood, Siddharth Rana, Niall Tumity, Fu-Gow Tarntair, Catherine Langpoklakpam, Hao-Chung Kuo, Jitendra Pratap Singh
Summary: Conductive β-Ga2O3 epilayers grown on the sapphire substrate using MOCVD were studied by Si-ion implanted. A metal-insulator-semiconductor diode (MISD) was fabricated using undoped and Si-implanted β-Ga2O3 epitaxial layer. The electrical and carrier transport properties of different MISD with different distance between cathode and anode contact were investigated.
MATERIALS TODAY ADVANCES
(2023)
Article
Materials Science, Coatings & Films
Lu Lu, Weiwei Meng, Yingmin Wang, Jianbing Qiang, Shao-Bo Mi
Summary: The atomic-scale structure properties of the epitaxial growth of wurtzite ZnO film on an a-plane sapphire substrate were investigated using transmission electron microscopy. A crystallographic orientation relationship between the ZnO film and alpha-Al2O3 substrate was determined. Different heterointerface structures and ZnO domains with opposite lattice polarity were formed due to the two types of oxygen-terminated alpha-Al2O3 substrate surfaces. The coalescence of opposite polarity domains resulted in the appearance of inversion domain boundaries and kinks during the propagation of these boundaries.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Chemistry, Physical
Bin Liu, Yali Zhou, Qi Luo, Heqing Yang, Shengzhong Liu
Summary: The experimental observation of pressure-induced structural changes in ZnO non-polar (10 (1) over bar0) crystal plane reveals the in-plane anisotropic piezoelectric behavior. Piezoelectric and rectification effects are observed in the [0001] polar direction, but not in the [1 (2) over bar 10] non-polar direction perpendicular to it. Pressure reduces or eliminates the piezoelectric and rectification properties in the [0001] direction. The origin of the piezoelectric effect is attributed to the spontaneous polarization in the [0001] direction. Additionally, pressure-induced structural changes in ZnO are observed for the first time.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Physics, Multidisciplinary
Luis Villamagua, Richard Rivera, Frank Maldonado, Jessica Cuesta, Carlos Tapia, Manuela Carini
Summary: The molecular adsorption of ethanethiol on the nonpolar ZnO surface was studied using density functional theory, with the presence of an oxygen vacancy triggering the appearance of an F-center. The analysis identified three different adsorption patterns, including dissociative and non-dissociative chemisorption with varying adsorption energies, as well as physisorption.
Article
Chemistry, Multidisciplinary
Hoki Son, Ye-ji Choi, Soon-Ku Hong, Ji-Hyeon Park, Dae-Woo Jeon
Summary: This study found that alpha-Ga2O3 grown on conical frustum-patterned sapphire substrates exhibited better crystal quality compared to those grown on conventional sapphire substrates, with improvements in surface morphology and reduction in threading dislocation propagation.
Article
Physics, Applied
P. John, P. Vennegues, H. Rotella, C. Deparis, C. Lichtensteiger, J. Zuniga-Perez
Summary: Epitaxial growth of Mg3N2 thin films by molecular beam epitaxy has been achieved, with the microstructure displaying column twist but narrow rocking curve peaks do not necessarily indicate high crystalline quality.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
P. John, M. Al Khalfioui, C. Deparis, A. Welk, C. Lichtensteiger, R. Bachelet, G. Saint-Girons, H. Rotella, M. Hugues, M. Grundmann, J. Zuniga-Perez
Summary: Single-crystalline Zn3N2 thin films were successfully grown on MgO and YSZ substrates with different orientations achieved depending on growth conditions. The films exhibited systematic n-type and degenerate behavior with varying carrier concentrations and electron mobilities, leading to optical bandgaps in the range of 1.05-1.37 eV. Hall effect measurements showed that ionized impurity scattering was the main limiting factor for mobility in the films.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Multidisciplinary Sciences
Qinghua Song, Mutasem Odeh, Jesus Zuniga-Perez, Boubacar Kante, Patrice Genevet
Summary: By exploiting the topological features of non-Hermitian matrices near singular points, an additional degree of freedom was introduced to address optical phase engineering in optical metasurfaces. Choosing metasurface building blocks to encircle a singularity allowed for the engineered full 2π-phase on a specific reflected polarization channel with topological protection. The ease of implementation and compatibility with other phase-addressing mechanisms demonstrate the industrial applicability of topological properties in metasurface technology at optical frequencies.
Article
Physics, Applied
C. A. Sgroi, J. Brault, J. -Y. Duboz, S. Chenot, P. Vennegues, A. Ludwig, A. D. Wieck
Summary: We present capacitance-voltage measurements of self-assembled wurtzite-GaN quantum dots (QDs). The QDs are embedded in a charge-tunable diode structure and were grown by molecular beam epitaxy using the Stranski-Krastanov growth method. The study shows that charges and the internal electric fields influence the energy spacing in the QDs and demonstrates the possibility of achieving single-electron charging and Coulomb blockade energy in the QDs at room temperature.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Multidisciplinary
Leo Mallet-Dida, Pierre Disseix, Francois Reveret, Francois Medard, Blandine Alloing, Jesus Zuniga-Perez, Joel Leymarie
Summary: This paper investigates the bleaching phenomenon of excitons in high-quality GaN samples under high excitation intensities. Through micro-photoluminescence and time-resolved experiments, the effect of excitation intensity on carrier lifetime is studied, and the occurrence of a Mott transition at a specific carrier concentration is discovered.
NEW JOURNAL OF PHYSICS
(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
Chemistry, Multidisciplinary
Xiaodan Lyu, Qinghai Tan, Lishu Wu, Chusheng Zhang, Zhaowei Zhang, Zhao Mu, Jesus Zuniga-Perez, Hongbing Cai, Weibo Gao
Summary: This study investigates the strain properties of boron vacancy centers in hexagonal boron nitride using optical and Raman spectroscopy techniques, demonstrating their potential for quantum sensing and in situ imaging of strain under working conditions.
Article
Physics, Applied
H. Souissi, M. Gromovyi, T. Gueye, C. Brimont, L. Doyennette, D. D. Solnyshkov, G. Malpuech, E. Cambril, S. Bouchoule, B. Alloing, S. Rennesson, F. Semond, J. Zuniga-Perez, T. Guillet
Summary: In this study, we experimentally demonstrate the difference between a ridge polariton laser and a conventional edge-emitting ridge laser operating under electron-hole population inversion. We find that the laser effect can be achieved in a ridge polariton laser with just 15% of the cavity length used as an exciton reservoir, whereas this would not be possible in a conventional ridge laser. We also observe that the polaritonic gain in the ridge polariton laser is about 10 times larger than that in equivalent GaN lasers.
PHYSICAL REVIEW APPLIED
(2022)
Article
Crystallography
Jean Massies, Wanda Isnard, Jesus Zuniga-Perez, Jean-Yves Duboz
Summary: We used kinetic Monte Carlo simulations to model the growth of InGaN alloys on perfectly oriented and misoriented GaN surfaces. As the temperature increases, we observed two phenomena: composition pulling along the growth direction and lateral indium rich cluster formation. Both phenomena are caused by strain, and temperature enables their manifestation. The transition from statistical alloys to heterogeneous layers with indium rich clusters occurs as the growth temperature increases, and this transition can be quantified using a cluster index based on the spatial distribution of In and Ga atoms.
JOURNAL OF CRYSTAL GROWTH
(2023)
Article
Chemistry, Multidisciplinary
Ruihua He, Max Meunier, Zhaogang Dong, Hongbing Cai, Weibo Gao, Jesus Zuniga-Perez, Xiaogang Liu
Summary: Inorganic halide perovskite quantum dots have been widely used as efficient active materials in optoelectronic applications. In this work, we coupled a layer of perovskite quantum dots to dielectric Mie resonators to simultaneously exploit the Purcell effect and increase light extraction, resulting in an 18-fold increase in luminescence. Our numerical simulations and experimental measurements revealed the interplay of these two effects and provided guiding principles for maximizing the output intensity of quantum emitters and classical emitters in perovskite-based optoelectronic devices.
Article
Nanoscience & Nanotechnology
Max Meunier, John J. H. Eng, Zhao Mu, Sebastien Chenot, Virginie Brandli, Philippe de Mierry, Weibo Gao, Jesus Zuniga-Perez
Summary: In 2018, a new single-photon source with high potential was discovered in gallium nitride, offering telecom wavelength emission, record-high brightness, good purity, and operation at room temperature. This article discusses the challenges associated with a low spatial density and a spectrally wide distribution of emitters in GaN layers, and describes the design and fabrication of bullseye antennas. The findings demonstrate that telecom single-photon emitters in GaN are well adapted for single-photon applications, but highlight the numerous difficulties that still need to be overcome for actual quantum photonic applications.
Article
Physics, Applied
Kilian Baril, Pierre-Marie Coulon, Mrad Mrad, Nabil Labchir, Guy Feuillet, Matthew Charles, Cecile Gourgon, Philippe Vennegues, Jesus Zuniga-Perez, Blandine Alloing
Summary: In this paper, three pendeo-epitaxy growth approaches were used to reduce the threading dislocation density (TDD) of 20 x 20 μm² GaN platelets for micro light-emitting diode (mu LED) development. The approach relied on the coalescence of GaN crystallites grown on deformable pillars etched into a silicon-on-insulator substrate. By taking advantage of the creeping properties of SiO2 at GaN epitaxial growth temperature, the crystallites were aligned and grain boundary dislocations were reduced. Additionally, this bottom-up approach eliminated the need for dry plasma etching in mu LED fabrication, which typically deteriorates sidewalls and reduces display efficiency.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Geoffrey Kreyder, Lea Hermet, Pierre Disseix, Francois Medard, Martine Mihailovic, Francois Reveret, Sophie Bouchoule, Christiane Deparis, Jesus Zuniga-Perez, Joel Leymarie
Summary: The study proposes the use of coherent emission of exciton polaritons to lower the lasing threshold, eliminating the need for exciton dissociation in a classical semiconductor laser. The researchers combined experimental measurements with a model that includes changes in permittivity based on carrier density to clearly demonstrate the polaritonic nature of lasing. The study used angle-resolved photoluminescence to observe and monitor the shift in polaritonic dispersion towards photonic dispersion as pump optical intensity increased, supported by a model accounting for oscillator strength reduction and band gap renormalization. Measurement of carrier lifetime at optical intensities during polariton lasing confirmed lower carrier density than reported Mott density for zinc oxide.
Proceedings Paper
Engineering, Electrical & Electronic
T. Guillet, H. Souissi, M. Gromovyi, T. Gueye, C. Brimont, L. Doyennette, G. Kreyder, F. Reveret, P. Disseix, F. Medard, J. Leymarie, G. Malpuech, D. Solnyshkov, B. Alloing, S. Rennesson, F. Semond, J. Zuniga-Perez, E. Cambril, S. Bouchoule
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Article
Physics, Multidisciplinary
O. Herrfurth, S. Richter, M. Rebarz, S. Espinoza, J. Zuniga-Perez, C. Deparis, J. Leveillee, A. Schleife, M. Grundmann, J. Andreasson, R. Schmidt-Grund
Summary: The full transient dielectric-function (DF) tensor of ZnO after UV-laser excitation is obtained by femtosecond time-resolved spectroscopic ellipsometry, showing pump-induced switching from positive to negative birefringence and contributions of inter-valence-band transitions. Line-shape analysis above the band gap reveals a maximal dynamic increase in the transient exciton energy and exponential Urbach-rule absorption below the band gap.
PHYSICAL REVIEW RESEARCH
(2021)