Article
Crystallography
Anthony Rice, Kirstin Alberi
Summary: Topological semimetals, with their unique combination of properties, have various applications in optoelectronics, spintronics, low energy computing, and catalysis. While they have been grown as high-quality bulk single crystals, their integration with semiconductor substrates is necessary for maximizing their technological potential. This study demonstrates the epitaxial growth of the Dirac semimetal Cd3As2 on Si(001) through two different routes. This work lays the foundation for integrating novel semimetal materials with existing CMOS technology.
Article
Chemistry, Multidisciplinary
Junjun Wang, Xin Huang, Honglin Zhang, Linqing Wang, Weijiu Huang, Shaofu Kuang, Fuxiang Huang
Summary: The study investigated the peeling process of coatings by using first-principles calculations to analyze the work of adhesion, interface energy, and electronic structure. Results showed that the diamond-Si interface exhibited better performance, while the Ti-Ti interface was most prone to deformation, and the Si-Ti interface was more likely to delaminate.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Chemistry, Multidisciplinary
Maximilian Kolhep, Juergen Blaesing, Andre Strittmatter, Margit Zacharias
Summary: This study reports on the spontaneous and position-controlled epitaxial growth of highly oriented ZnO nanowires on Si substrate using a catalyst-free CVD approach with an AlN buffer layer and a ZnO seed layer. By adjusting the growth parameters, the size and density of the nanowires can be controlled while maintaining their non-tapered and uniform hexagonal shape. High-resolution X-ray diffraction and omega-scans confirmed the low crystal tilt and twist of the nanowires.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Multidisciplinary Sciences
Zhen Wang, Jinho Byun, Subin Lee, Jinsol Seo, Bumsu Park, Jong Chan Kim, Hu Young Jeong, Junhyeok Bang, Jaekwang Lee, Sang Ho Oh
Summary: This study investigates the characteristics of ZnO polar surfaces and their influence on the evaporation and crystal growth of ZnO nanostructures. The results demonstrate that the evaporation and crystal growth rates of ZnO vary significantly on different surfaces, with the Zn-terminated ZnO (0001) polar surface exhibiting the fastest rates. The evaporation process on the polar surface accelerates dramatically at approximately 300 degrees C, resulting in the formation of a few nanometer-thick quasi-liquid layer. This quasi-liquid layer controls the dissociative evaporation of ZnO by reacting with Zn and O-2 vapors and the underlying ZnO crystal, and facilitates the desorption of O-2 molecules by catalyzing the disordering of the ZnO lattice.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Jian-Huan Wang, Ting Wang, Jian-Jun Zhang
Summary: Controllable growth of wafer-scale in-plane nanowires is demonstrated by introducing molecular beam epitaxy on patterned Si structures, resulting in highly homogeneous Si, SiGe, and Ge/Si core/shell NW arrays with well-defined facets. Suspended Si NWs with four {111} facets and a side width of about 25 nm are observed, confirming the high quality of these epitaxial NWs through characterizations including high resolution transmission electron microscopy.
Article
Energy & Fuels
Nicolas Barreau, Olivier Durand, Eugene Bertin, Antoine Letoublon, Charles Cornet, Polyxeni Tsoulka, Eric Gautron, Daniel Lincot
Summary: This study investigates the epitaxial growth of Cu(In,Ga)Se2 films (CIGSe) onto GaP/Si(001) pseudosubstrates using co-evaporation, with GaP thin layer epitaxially grown by Molecular Beam Epitaxy (MBE). Extensive structural characterization of epi-CIGSe is performed through X-ray diffraction and transmission electron microscopy, revealing strong evidence of epitaxial growth of CIGSe on (GaP/Si)(001) and the propagation of twins from the GaP/Si interface through the CIGSe/GaP interface. This research aims to pave the way for future CIGSe/GaP/Si structures for tandem solar cells with c-Si bottom cell and GaP interfacial buffer layer, facilitating high-quality CIGSe epitaxial growth as a thin film top cell absorber.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Chemistry, Physical
Zhengfeng Ren, Shandong Qi, Hua Zhou, Shishen Yan, Mingchun Xu, Shujun Hu
Summary: In this study, the researchers combined microchannel plate low-energy electron diffraction (MCP-LEED), CO2 molecule probe based on polarization-resolved infrared reflection adsorption spectra (PR-IRRAS), and first-principles calculations to systematically study the ZnO(0001) polar surface. They achieved five clear periodic surface structures depending on hydrogen coverage and tracked the surface atomic configuration evolutions using a CO2 infrared probe. The first-principles calculations revealed the role of surface hydrogens in stabilizing the hydrogen covered ZnO(0001) polar surface.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Jin Yuan, Jian-Qing Dai, Cheng Ke, Zi-Cheng Wei
Summary: This study reveals an unusual charge doping effect in graphene on the ferroelectric BiAlO3(0001) polar surfaces, where the positive surface induces p-type carriers and the negative surface induces n-type carriers in graphene. The specific band arrangement between graphene and the ferroelectric polar surface determines the carrier type and density in graphene in Gr/FE system. Additionally, the study predicts the potential use of Gr/BiAlO3(0001) systems to fabricate graphene p-n homojunctions by engineering the domain pattern in the ferroelectric substrate.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Peijiao Fang, Baiwei Wang, C. P. Mulligan, T. M. Murray, S. Khare, Daniel Gall
Summary: In this study, tungsten carbide films were sputter-deposited onto Mg0(001) substrates at 400 degrees C in Ar - CH4 gas mixtures. The films were found to contain amorphous carbon and carbon vacancies. The epitaxial relationship between the cubic WCy phase layers and the substrate was demonstrated through X-ray diffraction and transmission electron microscopy analyses.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Ludiane Lima, Lucas de S. Caldas, Astrid Ali, Jade Barreto, Roberto Freitas, Aline Mazzarella, Guilherme Felix, Victor Carozo, Fernando Stavale
Summary: The research discovered that ultrathin ZnO films on Ag substrates exhibit well-defined stoichiometry and crystal phases, with Raman spectroscopy showing a substantial enhancement of Raman combination modes. The electronic and structural properties of finite-size films play a significant role in their vibrational properties, providing clues for understanding ZnO nanostructures.
Article
Physics, Applied
Dong Han, Wen-Qi Wei, Ming Ming, Zihao Wang, Ting Wang, Jian-Jun Zhang
Summary: In recent years, there has been a strong demand for GaSb-on-Si direct heteroepitaxy to expand the operating wavelength range to mid-infrared and high-mobility applications. However, the growth of high-quality GaSb films on Si is challenging due to the generation of high-density defects. In this study, we proposed a novel design and growth strategy to achieve the annihilation of antiphase boundaries (APBs) and the reduction of threading dislocation density (TDD) through the use of a V-grooved Si hollow structure and InGaSb/GaSb dislocation filtering layers. The reported results greatly improve the overall quality of epitaxial Si-based antimonide, benefiting various devices and critical applications.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Philipp Gribisch, Andreas Fissel
Summary: The structural and morphological properties of gadolinium oxide (Gd2O3) grown at high temperatures with molecular beam epitaxy on Si(001) were investigated for different stages of growth. The results suggest that the nanowire-like structures on Si(001) substrates have specific orientations, and the density and length can be tuned by changing the oxygen partial pressure.
Review
Materials Science, Coatings & Films
Wei Guo, Agham B. Posadas, Alexander A. Demkov
Summary: BaTiO3 (BTO) epitaxial material with a large Pockels coefficient is promising for silicon photonics applications. Understanding the influence of growth methods on the ferroelectric polarization direction is crucial for electro-optic modulators. Various deposition techniques have been used to grow BTO on Si, with resulting film structures and qualities summarized based on characterization results.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2021)
Article
Chemistry, Physical
J. E. Prieto, E. M. Trapero, P. Prieto, E. Garcia-Martin, G. D. Soria, P. Galan, J. de la Figuera
Summary: In this work, the growth of epitaxial Ru films on single-crystalline Al2O3 substrates by magnetron sputtering was investigated. The films were characterized using Rutherford backscattering spectrometry. The results showed that the thicker films exhibited a well-defined epitaxial relation with the substrate and high crystal quality, comparable to the Ru single crystal, while thinner films showed some degree of dechanneling.
APPLIED SURFACE SCIENCE
(2022)
Article
Energy & Fuels
Moritz L. Weber, Moritz Kindelmann, Egbert Wessel, Alexandros Sarantopoulos, Norbert H. Menzler, Regina Dittmann, Rainer Waser, Olivier Guillon, Christian Lenser, Felix Gunkel
Summary: Metal exsolution is a dynamic process driven by reducing atmosphere and elevated temperatures, which leads to the self-assembly of nanoparticles at the surface of complex perovskite catalysts. The characteristics of metal exsolution catalysts can be highly inhomogeneous, and the anisotropic surface properties of ceramic oxides have been found to significantly affect the exsolution behavior.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Materials Science, Multidisciplinary
Pratik Joshi, Parand R. Riley, Warren Denning, Shubhangi Shukla, Nayna Khosla, Jagdish Narayan, Roger Narayan
Summary: This study reports on the fabrication of highly adherent undoped and Si-containing DLC coatings on polyethylene substrates and explores their properties. The results show that Si-DLC coatings have higher interfacial shear strength and less cracking, improve the wettability of polyethylene, and have a higher optical bandgap. In addition, pulsed laser annealing can improve the lubricity, hydrophobicity, and electrical conductivity properties of the coatings, and can also form reduced graphene oxide on DLC thin films.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Nanoscience & Nanotechnology
Adele Moatti, Gabrielle Mineo-Foley, Siddharth Gupta, Ritesh Sachan, Jay Narayan
Summary: In this study, spin engineering was used to manipulate spin-related interactions in VO2 by introducing a ferromagnetic Ni layer. By controlling the shape anisotropy of the Ni layer, the structural pinning of VO2 was achieved while electronic and magnetic transitions took place.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
J. Narayan, N. Khosla
Summary: This paper reports the formation and self-organization of amorphous Q-carbon and Q-BN nanoballs, and discusses their properties and potential applications.
Article
Crystallography
Nayna Khosla, Jagdish Narayan
Summary: We have reported the successful formation of Q-carbon nanolayers, Q-carbon nanoballs, nanodiamonds, microdiamonds, and their composites by controlling laser and substrate variables. This study has important applications in various fields such as protective coatings, nanosensing, field emission, and targeted drug delivery.
Article
Nanoscience & Nanotechnology
Pratik Joshi, Shubhangi Shukla, Siddharth Gupta, Parand R. Riley, Jagdish Narayan, Roger Narayan
Summary: This study optimized the defect density of graphene by adjusting laser parameters, leading to improved detection limit for peroxide. Different treatment methods resulted in different graphene structures, with more holes leading to lower detection limits.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Parand R. Riley, Pratik Joshi, Nayna Khosla, Roger J. Narayan, Jagdish Narayan
Summary: In this study, highly uniform Q-carbon layers were formed through PECVD and ion bombardment, enabling wafer-scale integration. The conversion of Si-DLC films into Q-carbon was achieved by low-energy ion bombardment, resulting in the formation of diamond nucleation sites. If an epitaxial template is provided by the underlying substrate, wafer-scale growth of diamond epitaxial films can be realized.
Article
Materials Science, Ceramics
Parand R. Riley, Kai-Hung Yang, Yizhong Liu, Shelby A. Skoog, Jagdish Narayan, Roger J. Narayan
Summary: The surface chemistry of silicon-incorporated diamond-like carbon (Si-DLC) was modified by oxygen and fluorine plasma treatments, which increased the cell viability by converting the hydrophobic surface of Si-DLC into a hydrophilic one.
INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Siddharth Gupta, Pratik Joshi, Ritesh Sachan, Jagdish Narayan
Summary: This study demonstrates the fabrication of heterostructures with graphene and h-BN using laser irradiation. The results show that phase-pure h-BN and reduced graphene oxide films can be obtained through localized zone-refining. The newly fabricated diodes exhibit improved rectification and current flow characteristics compared to previous diodes, with increased turn-on voltage and low leakage current.
Article
Chemistry, Multidisciplinary
Jagdish Narayan, Roger Narayan
Summary: Screw dislocations play a significant role in the growth of crystalline structures and can become helical through the absorption of defects. By interacting with each other, these helical dislocations form double helices and contribute to the formation of nanostructures with large Eshelby twists. This research provides evidence for the formation of a double helix during thermal annealing and offers an explanation for the presence of large Eshelby twists in various nanowires. These screw dislocations also have implications for the formation of nanopipes and nanotubes with Eshelby twists in important materials used in solid-state devices.
Article
Nanoscience & Nanotechnology
Zehao Cui, Nayna Khosla, Tianxing Lai, Jagdish Narayan, Arumugam Manthiram
Summary: The cycling stability of high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) can be effectively enhanced by a high-energy laser treatment, which involves partial decomposition of the binder and formation of a surface LiF phase. This treatment mitigates detrimental electrode-electrolyte reactions and reduces the generation of dissolved transition-metal ions and acidic crossover species.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Nayna Khosla, Jagdish Narayan, Roger Narayan, Xiao-Guang Sun, Mariappan Parans Paranthaman
Summary: Nanosecond pulsed laser annealing improves cyclability and current carrying capacity of lithium-ion batteries by engineering microstructure and defects in graphite, and enhancing Li+ ion trapping sites.
Article
Electrochemistry
Nayna Khosla, Jagdish Narayan, Roger Narayan, Xiao-Guang Sun, M. Parans Paranthaman
Summary: In this study, nanosecond pulsed laser annealing (PLA) was used to improve the performance of lithium-ion batteries (LIBs). The PLA treatment reduced the carbonate layer, formed a protective LiF layer, and manipulated the microstructures of the cathodes to increase the active surface area. This resulted in up to a 50% increase in the current capacity of the batteries.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Jagdish Narayan, Siba Sundar Sahoo, Naveen Joshi, Roger Narayan
Summary: We have discovered Q-silicon, which has an atomic density 60% higher than crystalline silicon and maintains the same bonding characteristics. By randomly packing one, two, or three tetrahedra, distinct amorphous phases are formed, while a crystalline phase of Q-silicon is formed by arranging subunit cells along <110> directions with alternate holes. Quenching amorphous silicon in an undercooled state through nanosecond laser melting has resulted in Q-silicon with robust ferromagnetism compared to the diamagnetism of silicon. The estimated blocking temperature of Q-silicon is above 400 K, opening up new possibilities for spin-based computing and atomic-level storage.
MATERIALS RESEARCH LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Ariful Haque, Yanming Liu, Saif Taqy, Jay Narayan
Summary: Researchers have successfully synthesized functional diamond microstructures and coatings, including diamond microfibers, microspheres, tubes, and thin films, using amorphous and graphitic carbon precursors via hot filament chemical vapor deposition. The characteristics of the microstructures depend on the initial carbon precursors and laser annealing pretreatments. Low-cost and abundant carbon precursors act as nucleation sites and accelerate diamond growth, while laser annealing further promotes nucleation and growth. The prepared diamond microstructures exhibit excellent diamond quality as confirmed by electron backscatter diffraction and Raman spectroscopy.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Pratik Joshi, Shubhangi Shukla, Siddharth Gupta, Naveen Joshi, Jagdish Narayan, Roger Narayan
Summary: We present a novel method using excimer laser to fabricate crystalline MoS2 nanoneedles. Laser annealing at a low energy density led to a closed-pack structure with low defects and excellent conductivity. Increasing the laser annealing energy density resulted in the formation of MoS2 nano-needles. The MoS2 nano-needles showed remarkable reduction ability for H2O2 and demonstrated low detection limit and high sensitivity.
MRS COMMUNICATIONS
(2023)
