Publications by authors named "Phuc H"

Article Synopsis
  • The study examines the electronic properties and contact behavior of graphene/γ-GeSe heterostructures using first-principles calculations under electric fields and strains.
  • At equilibrium, the heterostructure exhibits a p-type Schottky contact with a low barrier, ideal for low-resistance electronic devices.
  • Applying electric fields and adjusting strains can switch contact types from p-type to n-type or even to Ohmic contact, opening up opportunities for enhancing device performance through tunable electronic properties.
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Two-dimensional materials and their combined heterostructures have paved the way for numerous next-generation electronic and optoelectronic applications. Herein, we performed first principles calculations to computationally design the MoSe/WS heterostructure and consider its geometric structure, electronic properties and contact behavior, as well as the effects of the electric fields and strain. Our results show that the MoSe/WS heterostructure is energetically, thermodynamically and mechanically stable.

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In the present work, we propose GaGeX (X = N, P, As) monolayers and explore their structural, vibrational, piezoelectric, electronic, and transport characteristics for multifunctional applications based on first-principles simulations. Our analyses of cohesive energy, phonon dispersion spectra, and molecular dynamics simulations indicate that the three proposed structures have good energetic, dynamic, and thermodynamic stabilities. The GaGeX are found as piezoelectric materials with high piezoelectric coefficient of -1.

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Three-dimensional (3D) bioprinting has emerged as a promising strategy for fabricating complex tissue analogs with intricate architectures, such as vascular networks. Achieving this necessitates bioink formulations that possess highly printable properties and provide a cell-friendly microenvironment mimicking the native extracellular matrix. Rapid advancements in printing techniques continue to expand the capabilities of researchers, enabling them to overcome existing biological barriers.

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Recently, searching for a metal-semiconductor junction (MSJ) that exhibits low-contact resistance has received tremendous consideration, as they are essential components in next-generation field-effect transistors. In this work, we design a MSJ by integrating two-dimensional (2D) graphene as the metallic electrode and 2D Janus γ-GeSSe as the semiconducting channel using first-principles simulations. All the graphene/γ-GeSSe MSJs are predicted to be energetically, mechanically, and thermodynamically stable, characterized by the weak van der Waals (vdW) interactions.

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Obstetric ultrasound is an important tool in managing pregnancies and its use is increasing globally. However, the status of the pregnant woman and the fetus may vary in terms of clinical management, views in the community and legislation. To investigate the views and experiences of Vietnamese health professionals on maternal and fetal health interests, priority setting and potential conflicts, we conducted a cross-sectional study using a structured questionnaire.

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Minimizing the contact barriers at the interface, forming between two different two-dimensional metals and semiconductors, is essential for designing high-performance optoelectronic devices. In this work, we design different types of metal-semiconductor heterostructures by combining 2D metallic MX (M = Nb, Hf; X = S, Se) and 2D semiconductor SiH and investigate systematically their electronic properties and contact characteristics using first principles calculations. We find that all the MX/SiH (M = Nb, Ta; X = S, Se) heterostructures are energetically stable, suggesting that they could potentially be synthesized in the future.

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Breaking structural symmetry in two-dimensional layered Janus materials can result in enhanced new phenomena and create additional degrees of piezoelectric responses. In this study, we theoretically design a series of Janus monolayers HfGeZH (Z = N, P, As) and investigate their structural characteristics, crystal stability, piezoelectric responses, electronic features, and carrier mobility using first-principles calculations. Phonon dispersion analysis confirms that HfGeZH monolayers are dynamically stable and their mechanical stability is also confirmed through the Born-Huang criteria.

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Article Synopsis
  • The article investigates new materials for piezoelectric and electronic devices by analyzing Janus ZrGeZH monolayers (where Z = N, P, As) using density functional theory calculations.
  • The study confirms the stability of these materials through various simulations, revealing that they are indirect band gap semiconductors with band gap energies of about 1.15 eV for ZrGePH and 1.00 eV for ZrGeAsH.
  • The research highlights the promising piezoelectric properties and high electron mobility of these monolayers, indicating their potential use in advanced technology applications.
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Two-dimensional (2D) van der Waals (vdW) heterostructures are considered as promising candidates for realizing multifunctional applications, including photodetectors, field effect transistors and solar cells. In this work, we performed first-principles calculations to design a 2D vdW MoTe/MoS heterostructure and investigate its electronic properties, contact types and the impact of an electric field and in-plane biaxial strain. We find that the MoTe/MoS heterostructure is predicted to be structurally, thermally and mechanically stable.

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This study addresses the effect of electron-phonon coupling (EPC) on the electro-optical properties of gated β-borophene. The focus is on how EPC influences the orbital hybridization of boron atoms, particularly within the Bariśic-Labbe-Friedel-Su-Schrieffer-Heeger framework, and considers the role of gate electrodes in this process. The results reveal a redshift in the optical spectrum only when there is positive feedback from one electrode on EPC.

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In this study, using the tight-binding model and Green's function technique, we investigate potential electronic phase transitions in bilayer 6 borophene under the influence of external stimuli, including a perpendicular electric field, electron-hole coupling between sublayers (excitonic effects), and dopants. Our focus is on key electronic properties such as the band structure and density of states. Our findings reveal that the pristine lattice is metal with Dirac cones around the Fermi level, where their intersection forms a nodal line.

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Two-dimensional (2D) metallic TaSe and semiconducting WSe materials have been successfully fabricated in experiments and are considered as promising contact and channel materials, respectively, for the design of next-generation electronic devices. Herein, we design a metal-semiconductor (M-S) heterostructure combining metallic TaSe and semiconducting WSe materials and investigate the atomic structure, electronic properties and controllable contact types of the combined TaSe/WSe M-S heterostructure using first-principles calculations. Our results reveal that the TaSe/WSe M-S heterostructure can adopt four different stable stacking configurations, all of which exhibit enhanced elastic constants compared to the constituent monolayers.

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The emergence of van der Waals (vdW) heterostructures, which consist of vertically stacked two-dimensional (2D) materials held together by weak vdW interactions, has introduced an innovative avenue for tailoring nanoelectronic devices. In this study, we have theoretically designed a metal/semiconductor heterostructure composed of NbS and Janus MoSSe, and conducted a thorough investigation of its electronic properties and the formation of contact barriers through first-principles calculations. The effects of stacking configurations and the influence of external electric fields in enhancing the tunability of the NbS/Janus MoSSe heterostructure are also explored.

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Conducting heterostructures have emerged as a promising strategy to enhance physical properties and unlock the potential application of such materials. Herein, we conduct and investigate the electronic and transport properties of the BSe/ScCF heterostructure using first-principles calculations. The BSe/ScCF heterostructure is structurally and thermodynamically stable, indicating that it can be feasible for further experiments.

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Article Synopsis
  • The rise in livestock production is expected to lead to the emergence of new pathogens that can affect both animal and human health.
  • Researchers studied the respiratory microbiota of pigs, focusing on a specific pathogen that is prevalent in pig farming and can also infect humans.
  • The findings indicate that certain pathogenic strains developed during the expansion of pig farming in the 19th and 20th centuries, spreading globally through the trade of live pigs and adapting over time to become more pathogenic.
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Article Synopsis
  • * Researchers analyzed 454 genomic samples from Vietnam and other locations, discovering that ST34 was introduced to Vietnam multiple times since 2000, leading to the emergence of five major clones that cause illnesses like diarrhea and bloodstream infections in children.
  • * The spread of ST34 is linked to the acquisition of resistance plasmids, which enable the bacteria to resist multiple drugs, positioning Southeast Asia as a critical area for monitoring the emergence of multidrug-resistant Salmonella strains.
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Two-dimensional (2D) metal-semiconductor heterostructures play a critical role in the development of modern electronics technology, offering a platform for tailored electronic behavior and enhanced device performance. Herein, we construct a novel 2D metal-semiconductor MoSH@MoS heterostructure and investigate its structures, electronic properties and contact characteristics using first-principles investigations. We find that the MoSH@MoS heterostructure exhibits a p-type Schottky contact, where the specific Schottky barrier height varies depending on the stacking configurations employed.

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Cadmium (Cd) pollution is a public environmental problem worthy of attention. Long-term exposure to Cd may have adverse effects on human health. Our previous study showed that urinary concentration of Cd (U-Cd) in the residents decreased when Cd-polluted paddy soil was removed.

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We theoretically study the role of adsorbed gas molecules on the electronic and optical properties of monolayer β-borophene with {a,b,c,d,e} atoms in its unit cell. We focus our attention on molecules NH, NO, NO, and CO, which provide additional states permitted by the host electrons. Utilizing the six-band tight-binding model based on an inversion symmetry (between {a,e} and {b,d} atoms) and the Kubo formalism, we survey the anisotropic electronic dispersion and the optical multi-interband spectrum produced by molecule-boron coupling.

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We study the transport properties of monolayers MoSiN, WSiN, and MoSiAsin a perpendicular magnetic field. The Landau level (LL) band structures including spin and exchange field effects are derived and discussed using a low-energy effective model. We show that the LLs band structures of these materials are similar to those of phosphorene and transition-metal dichalcogenides rather than graphene or silicene.

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Novel Janus materials have attracted broad interest due to the outstanding properties created by their out-of-plane asymmetry, with increasing theoretical exploration and more reports of successful fabrication in recent years. Here, we construct and explore the crystal structures, stabilities, electronic band structures, and transport properties - including carrier mobilities - of two-dimensional Janus MGeSiP (M = Ti, Zr, or Hf) monolayers based on density functional theory calculations. From the cohesive energies, elastic constants, and phonon dispersion calculations, the monolayers are confirmed to exhibit structural stability with high feasibility for experimental synthesis.

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Cadmium (Cd) is an environmental pollutant. Long-term exposure to Cd may lead to adverse health effects in humans. Our epidemiological studies showed that urinary Cd (U-Cd) concentrations increased from 2008 through 2014, although they decreased from 1986 through 2008.

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We discuss and examine the stability, electronic properties, and transport characteristics of asymmetric monolayers XWGeN (X = O, S, Se, Te) using density functional theory. All four monolayers of quintuple-layer atomic Janus XWGeN are predicted to be stable and they are all indirect semiconductors in the ground state. When the spin-orbit coupling (SOC) is included, a large spin splitting at the point is found in XWGeN monolayers, particularly, a giant Rashba-type spin splitting is observed around the point in three structures SWGeN, SeWGeN, and TeWGeN.

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