Article
Chemistry, Physical
Ricardo Jimenez-Sanchez, Sara E. Perez-Figueroa, Alejandro Trejo-Banos, Alvaro Miranda, Fernando Salazar, Miguel Cruz-Irisson
Summary: This study investigates the effects of surface Li on the electronic properties of H passivated GaAs nanowires using Density Functional Theory. The results show high binding energies and band gaps, which would hinder the application of GaAs nanowires in Li-ion batteries.
SURFACES AND INTERFACES
(2023)
Article
Physics, Applied
Maddaka Reddeppa, Chandrakalavathi Thota, Dong-Jin Nam, Hyeonseok Woo, Song-Gang Kim, Moon-Deock Kim
Summary: The use of a prototype V-groove textured Si(100) with (111) facets can significantly enhance the photocurrent density of GaN nanorods, as well as facilitate the trapping and modulation of light into the nanorods. Additionally, the heterostructure between GaN nanorods and V-groove textured Si promotes effective charge separation and transportation. This advancement represents a significant step forward in solar photoelectrolysis.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Lifan Shen, Huan Qian, Yanbin Yang, Yonghao Ma, Jun Deng, Yongzhe Zhang
Summary: High-quality InGaAs nanowires were synthesized by chemical vapor deposition and their surface was modified using simple wet chemistry. The modified nanowires showed significantly improved photoelectronic properties, with enhanced response time and photocurrent. This study offers important reference values for modulating surface states of ternary and multielement nanowires and improving the performance of nanoscale broadband photodetectors.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Physics, Multidisciplinary
Yuki Kobayashi, Christian Heide, Amalya C. Johnson, Vishal Tiwari, Fang Liu, David A. Reis, Tony F. Heinz, Shambhu Ghimire
Summary: Interactions between quantum materials and strong laser fields can result in non-equilibrium electronic states. Monolayer transition metal dichalcogenides, as direct-gap semiconductors with quantum confinement, offer opportunities for controlling excitons. However, characterizing strong-field driven exciton dynamics has been challenging.
Article
Chemistry, Multidisciplinary
Hongpeng Zhou, Deyun Zhang, Huichen Xie, Yang Liu, Caixia Meng, Pengfei Zhang, Fengtao Fan, Rengui Li, Can Li
Summary: Modulating oxygen vacancies in lead chromate semiconductor can enhance the charge separation and water oxidation activity. Oxygen vacancies introduce shallow and deep energy levels in the band structure, resulting in more surface trapped states. By controlling the oxygen chemical potentials, a photocurrent density of 3.43 mA cm(-2) at 1.23 V vs RHE is achieved.
ADVANCED MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Emre Usman, Mahsa Barzgar Vishlaghi, Abdullah Kahraman, Navid Solati, Sarp Kaya
Summary: The study demonstrates that the water oxidation activity of BiVO4 photoanode can be significantly boosted by a TiO2 overlayer prepared by atomic layer deposition. The TiO2 overlayer enhances charge separation and suppresses surface recombination, leading to a substantial improvement in photocurrent. This feature is particularly useful for wireless tandem devices for water splitting utilizing higher band gap photoanodes with front illumination.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Applied
Chen Huang, Fangzhou Liang, Huabin Yu, Meng Tian, Haochen Zhang, Tien Khee Ng, Boon S. Ooi, Haiding Sun
Summary: This study proposes an effective passivation approach using tetramethyl ammonium hydroxide (TMAH) solution treatment to improve the surface states of AlGaN quantum-disk nanowires (NWs) and successfully fabricates ultraviolet photodetectors (UV PDs) with excellent optical and electrical properties.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Kim Corinna Dumbgen, Juliette Zito, Ivan Infante, Zeger Hens
Summary: The relationship between the presence of undercoordinated surface atoms and the formation of localized trap states in InP quantum dots was analyzed using density functional theory. Removal of the surface passivation can lead to the formation of hole traps linked to 2-coordinated surface P and electron traps related to 2- or 3-coordinated surface P and 2-coordinated surface In. The concept of ionicity provides little guidance to understand the enhanced sensitivity of InP to trap-state formation, suggesting the need for more appropriate descriptors to predict the energetic position of atomic orbitals relative to band-edge states.
CHEMISTRY OF MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Shuai Li, Yu-Chen Zhang, Chi Zhang, Xi-Yuan Dai, Zhi-Yuan Yu, Fei Hu, Jadam Liu, Jian Sun, Ming Lu
Summary: The study shows that high-pressure Ar passivation enhances the photoluminescence of Si nanocrystals more effectively than H2 passivation, reducing the density of non-radiative recombination centers. Ar atoms can diffuse deeply into the sample, with the depth profile of enhancement correlating with Ar distribution. This effect is also observed with Kr passivation.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Physics, Applied
Minseok Choi, Chris G. Van de Walle
Summary: Using first-principles calculations, this study examines the energetics and electronic structure of fluorine in α-Al2O3. Fluorine can be incorporated as an interstitial or substitutional impurity and its behavior is influenced by the presence of aluminum. The study also investigates the impact of complexes formed between fluorine and hydrogen or carbon on Al2O3/semiconductor heterostructures.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Soumyadipta Rakshit, Boiko Cohen, Mario Gutierrez, Ala'a O. El-Ballouli, Abderrazzak Douhal
Summary: This study presents a simple synthesis method for blue emissive InP quantum dots using oleic acid and oleylamine as surface ligands, and subsequent coating with ZnS to increase their size and emission intensity. The pure phase synthesis of these quantum dots is confirmed using various characterization techniques. The study also investigates the energy pathways and fluorescence lifetimes of the quantum dots with different coating layers. These findings provide important insights for improving the emission efficiency of InP quantum dots and developing efficient UV-emissive light-emitting devices (LEDs).
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Xiaoxiao Li, Chenxuan Lou, Weijun Li, Lin Wang, Fengmei Gao, Gang Shao, Shanliang Chen, Weiyou Yang
Summary: This study introduces a high-performance field emitter with designed sharp corners, achieving a low E-to of 0.52 V/μm and a current fluctuation of only 2% over 10 hours. This design enhances electron emission sites and prevents damage during long-term operation.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Indy du Fosse, Simon C. Boehme, Ivan Infante, Arjan J. Houtepen
Summary: Trap states are crucial in colloidal quantum dot technologies, with metal-based trap nature remaining elusive. Photoexcitation can lead to the formation of metal-based traps in charge-neutral CdSe QDs, which are transient and can quench photoluminescence. This highlights the importance of surface redox reactions for the optical properties of QDs and the potential for photoexcitation to create transient in-gap states through atomic rearrangements on the surface.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Keisuke Minehisa, Ryo Murakami, Hidetoshi Hashimoto, Kaito Nakama, Kenta Sakaguchi, Rikuo Tsutsumi, Takeru Tanigawa, Mitsuki Yukimune, Kazuki Nagashima, Takeshi Yanagida, Shino Sato, Satoshi Hiura, Akihiro Murayama, Fumitaro Ishikawa
Summary: GaAs/AlGaAs core-shell nanowires with a diameter of 250 nm and a length of 6 μm were grown on 2-inch Si wafers using molecular beam epitaxy. The growth process did not require any specific pre-treatment. The Al-rich AlGaAs shells formed a native oxide protection layer, providing efficient passivation with elongated carrier lifetime. The homogenous and optically luminescent GaAs-related core-shell nanowires prepared using this method show promise for large-volume III-V heterostructure devices for integration with silicon.
NANOSCALE ADVANCES
(2023)
Article
Multidisciplinary Sciences
Yuxuan Li, Yaoyao Han, Wenfei Liang, Boyu Zhang, Yulu Li, Yuan Liu, Yupeng Yang, Kaifeng Wu, Jingyi Zhu
Summary: By controlling the light helicity, the researchers observed spin-selective Bloch-Siegert shift in CsPbI3 perovskite quantum dots, which was accompanied by a higher ratio between the Bloch-Siegert and optical Stark shifts than predicted by the non-interacting model. The experimental observations were quantitatively reproduced using a model that explicitly accounted for excitonic effects, suggesting the importance of many-body interactions in correctly modeling the shift. These findings provide a basis for implementing these effects in information processing, optical modulation, and Floquet engineering.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
M. Paillet, V. N. Popov, H. N. Tran, J. -c. Blancon, D. I. Levshov, R. Arenal, R. Parret, A. Ayari, A. San Miguel, F. Vallee, N. Del Fatti, A. A. Zahab, J. -l. Sauvajol
Summary: Double-walled carbon nanotubes are ideal structures to study interlayer coupling in one-dimensional systems. Through experiments and calculations, the nature of optical transitions in DWNTs can be determined, and the conditions for cross transitions can be identified. Raman spectroscopy is sensitive to electronic and mechanical coupling, making it a valuable tool for studying nanoscale systems.
Article
Chemistry, Multidisciplinary
Claudia M. Bazan, Anouk Beraud, Minh Nguyen, Amira Bencherif, Richard Martel, Delphine Bouilly
Summary: This study presents an innovative method using a gate electrode to control the surface functionalization of graphene devices. By dynamically adjusting the gate voltage, the reaction can be quickly initiated or suppressed, resulting in a high degree of homogeneity. This work demonstrates the powerful capability of the FET platform to study surface reactions on nanomaterials in real time.
Article
Engineering, Electrical & Electronic
Anthony Ayari, Pascal Vincent, Sorin Perisanu, Philippe Poncharal, Stephen T. Purcell
Summary: This study compared simulations of the Murphy and Good model with a new empirical equation for analyzing field emission data. The results showed that the validity of the new empirical equation is limited to a specific range of electric fields, calling into question the relationship between the work function and the constant parameter kappa.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2022)
Article
Engineering, Electrical & Electronic
M. Choueib, A. Derouet, P. Vincent, A. Ayari, S. Perisanu, P. Poncharal, C. S. Cojocaru, R. Martel, S. T. Purcell
Summary: This study reports a pronounced double negative differential resistance (NDR) phenomenon observed on highly crystalline p-type silicon nanowires, suggesting new functionalities for pulsing electron sources at high repetition rates.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2022)
Article
Chemistry, Multidisciplinary
A. Badon, J. -B Marceau, C. Allard, F. Fossard, A. Loiseau, L. Cognet, E. Flahaut, G. Recher, N. Izard, R. Martel, E. Gaufres
Summary: By confining alpha-sexithiophene (6T) molecules in boron nitride nanotubes (6T@BNNTs), fluorescence anisotropy can be induced in a transparent host. The experiments show that individual 6T@BNNTs exhibit high polarization extinction ratio at room temperature, and the fluorescence anisotropy is consistent with the alignment of encapsulated 6T molecules along the nanotube axis. By stretching a flexible transparent polymer film mixed with 6T@BNNTs, macroscopic fluorescence anisotropy can be induced within the film. This work demonstrates the use of dyes@BNNT system as a convenient platform to induce fluorescence anisotropy in photonic materials.
MATERIALS HORIZONS
(2023)
Article
Engineering, Electrical & Electronic
Fanny Casteignau, Taki Aissou, Jerome Menneveux, Jocelyn Veilleux, Richard Martel, Nadi Braidy
Summary: This study investigates the fabrication of carbon nanohorns (CNHs) using different promotor gases in an inductively coupled plasma. The results show that the nature of the promotor gas directly influences the morphology and occurrence of CNHs. Quantitative transmission electron microscopy reveals that CNHs are favored by a promotor:precursor ratio of 0.5, particularly when using nitrogen or helium as the promotor gas. Optical emission spectroscopy confirms that the promotor gas strongly modulates the C-2 density and temperature profile of the plasma torch.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2022)
Editorial Material
Electrochemistry
Mariam Ezzedine, Fatme Jardali, Ileana Florea, Zamfir Mihai-Robert, Cojocaru Costel-Sorin
Summary: In this study, a hybrid nanostructured anode based on silicon nanoparticles (SiNPs) anchored on vertically aligned carbon nanotubes (VACNTs) was synthesized on a commercial macroscopic current collector. The capacity stability of the electrode was improved by adjusting the SiNPs deposition time or the VACNTs length. By increasing the VACNTs length, a higher gravimetric capacity and higher areal loading mass of silicon were achieved without compromising cycling stability. This hybrid nanostructured electrode exhibited excellent stability with a reversible capacity of 1330 mAh g(-1) after 2000 cycles.
BATTERIES & SUPERCAPS
(2023)
Article
Engineering, Electrical & Electronic
Anthony Ayari, Pascal Vincent, Sorin Perisanu, Philippe Poncharal, Stephen T. T. Purcell
Summary: Representing field emission data on a Fowler-Nordheim plot is not recommended due to spurious estimation of emitter parameters. The uncertainty in the estimation of the field enhancement factor or the emission area can be as high as +/- 50%. Advanced analysis methods based on differential conductance measurement are demanding in terms of emitter stability.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Nanoscience & Nanotechnology
Suraj Mal, Layane Duarte e Souza, Charlotte Allard, Carolane David, Sebastien Blais-Ouellette, Louis Gaboury, Nathalie Y. -W. Tang, Richard Martel
Summary: Researchers designed, synthesized, and characterized a Raman nanoprobe made of dye-sensitized single-walled carbon nanotubes (SWCNTs) for selectively targeting biomarkers of breast cancer cells. The nanoprobe consisted of Raman-active dyes encapsulated inside a SWCNT and covalently grafted with poly(ethylene glycol) (PEG). Two distinct nanoprobes were prepared by covalently binding alpha-sexithiophene- and beta-carotene-derived nanoprobes to anti-E-cadherin (E-cad) or anti-keratin-19 (KRT19) antibodies, which specifically recognize biomarkers on breast cancer cells. Hyperspectral imaging of specific Raman bands allowed for simultaneous detection of the nanoprobe duplex on target cells without the need for additional filters or subsequent incubation steps.
ACS APPLIED BIO MATERIALS
(2023)
Article
Chemistry, Physical
Pascal Vincent, Federico Panciera, Ileana Florea, Nicholas Blanchard, Costel Sorin Cojocaru, Mariam Ezzedine, Haifa Taoum, Sorin Perisanu, Pierre De Laharpe, Anthony Ayari, Julien Chaste, Khakimjon Saidov, Utkur Mirsaidov, Stephen Thomas Purcell, Pierre Legagneux
Summary: In this study, we observed in real time the aligning effect of electric fields during the synthesis of carbon nanotubes using an environmental transmission electron microscope. The nanotubes showed excellent alignment and allowed for accurate determination of growth rates. Different growth behaviors were observed, including constant growth rates and acceleration. The mechanisms behind these behaviors, as well as the balance between electrostatic and adhesion forces, were discussed.
Article
Nanoscience & Nanotechnology
Andjelika Bjelajac, Ileana Florea, Mihai Zamfir, Sandrine Tusseau Nenez, Costel Sorin Cojocaru
Summary: In this study, vertically aligned multiwall carbon nanotubes (CNTs) films were used as support for ZnO/ZnS photocatalytic active nanostructures. The CNTs were synthesized using a hot-filament chemical vapor deposition (HfCVD) method. Point defects in the CNTs outer walls were created using a low pressure nonthermal water vapors diffusive plasma, and Zn nanoparticles were subsequently electrodeposited onto the CNTs. The samples were annealed to obtain ZnO, ZnS, and a mix phase of ZnO/ZnS. The absorption of ZnO was enhanced by S doping and involvement of CNTs, and the ZnO1-xSx@CNTs heteronanostructure showed the highest photocatalytic activity for methyl blue dye degradation among the studied samples.
Article
Electrochemistry
Mariam Ezzedine, Fatme Jardali, Ileana Florea, Mihai-Robert Zamfir, Costel-Sorin Cojocaru
Summary: The study presents a hybrid nanostructured electrode based on silicon nanoparticles and carbon nanotubes, which improves the capacity stability of the electrode by tuning the active silicon areal loading, and achieves a higher gravimetric capacity and higher areal loading mass of silicon.
BATTERIES & SUPERCAPS
(2023)
