Article
Nanoscience & Nanotechnology
Naoki Higashitarumizu, Shiekh Zia Uddin, Daniel Weinberg, Nima Sefidmooye Azar, I. K. M. Reaz Rahman, Vivian Wang, Kenneth B. B. Crozier, Eran Rabani, Ali Javey
Summary: The photophysics of black phosphorus, an optoelectronic material, was investigated. It was found that the photoluminescence quantum yield initially decreases with decreasing thickness due to enhanced surface carrier recombination, but sharply increases afterwards. Furthermore, black phosphorus exhibits a much lower surface carrier recombination velocity compared to other semiconductors.
NATURE NANOTECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Ramy El-Bashar, Mohamed Hussein, Salem F. Hegazy, Yehia Badr, B. M. A. Rahman, Kenneth T. Grattan, Mohamed Farhat O. Hameed, Salah S. A. Obayya
Summary: The electrical characteristics of quad-crescent-shaped silicon nanowire solar cells were analyzed numerically to optimize performance, resulting in increased optical absorption and power conversion efficiency. The core-shell junction design showed an improvement of approximately 80% in conversion efficiency due to the high back surface field layer, with minimal impact from nanowire surface recombination compared to the axial junction.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Applied
Xiao Li, Xuezhe Yu, Haotian Zeng, Giorgos Boras, Kai Shen, Yunyan Zhang, Jiang Wu, Kwang Leong Choy, Huiyun Liu
Summary: GaAs nanowire-based metal-semiconductor-metal photodetectors achieve enhanced photoresponsivity and reduced response time through surface treatment and interfacial contact optimization. The design demonstrates good repeatability of dynamic photo-switching characteristics and stability, making GaAs nanowires a promising candidate for high-performance and reliable nano-photodetection in the visible range.
APPLIED PHYSICS LETTERS
(2021)
Article
Nuclear Science & Technology
B. Park, Y. Kim, J. Seo, J. Byun, K. Kim
Summary: This study fabricated radiation detectors using CZT crystals and carried out wet passivation with NaOCl on the Br-etched detectors. It was found that passivation improved the transport property and enhanced the performance of the detectors.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Archana Sinha, Jiadong Qian, Stephanie L. Moffitt, Katherine Hurst, Kent Terwilliger, David C. Miller, Laura T. Schelhas, Peter Hacke
Summary: Degradation from ultraviolet radiation has become prevalent in the front of solar cells due to the use of UV-transmitting encapsulants. This study examines UV-induced degradation in various commercial crystalline silicon cell technologies and finds that modern cell architectures are more vulnerable to UV damage, leading to a significant decrease in power. Bifacial cells with rear-side exposure show a greater power decrease, indicating that the rear side is more susceptible to UV damage.
PROGRESS IN PHOTOVOLTAICS
(2023)
Article
Chemistry, Multidisciplinary
Mariana Zavarize, Nikolai V. V. Sibirev, Yury Berdnikov, Murilo Moreira, Helio T. Obata, Varlei Rodrigues, Vladimir G. G. Dubrovskii, Monica A. Cotta
Summary: InP nanowires were catalyzed by Au, Ag, and Au-Ag nanoparticles on GaAs substrates with different orientations. Statistical analysis and modeling demonstrated that the ratio of droplet surface density to In precursor flux is critical in controlling nanowire growth mode and orientation. These findings enhance our understanding of planar nanowire vapor-liquid-solid growth and provide tools for controlling III-V nanowire growth on lattice-mismatched substrates.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Energy & Fuels
Naeimeh Mozaffari, The Duong, M. M. Shehata, Anh Dinh Bui, Huyen T. Pham, Yanting Yin, Y. Osorio Mayon, Jianghui Zheng, Md Arafat Mahmud, Grace Dansoa Tabi, Gunther G. Andersson, Lachlan E. Black, Jun Peng, Heping Shen, Thomas P. White, Klaus Weber, Kylie R. Catchpole
Summary: Dimensional engineering technique is an efficient method to improve the performance of perovskite solar cells. This study presents a passivation approach for the perovskite/hole transport layer interface using a mixture of guanidinium and n-octylammonium cations. The dual-cation passivation layer provides higher voltage and efficiency, as well as better stability, with a more hydrophobic and smoother surface.
Article
Energy & Fuels
Andreas Wolf, Julian Egle, Sebastian Mack, Hannes Hoffler, David Herrmann, Sabrina Lohmuller, Joerg Horzel, Andreas Fell
Summary: This study focuses on the effective surface recombination velocity of alkaline textured, Phosphorus-diffused, and thermal SiO2/SiNx passivated surfaces with an emphasis on the impact of the thermal oxidation temperature. By applying a recent calibration procedure for carrier lifetime measurements, precise determination of the dark saturation current density was achieved. Experimental results from various diffusion/oxidation process combinations provide a dataset for revising the parameterization of the effective surface recombination velocity and investigating the impact of oxidation temperature on passivation quality, including the modeling of fixed surface charges.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Physics, Applied
I. R. Hooper, E. Khorani, X. Romain, L. E. Barr, T. Niewelt, S. Saxena, A. Wratten, N. E. Grant, J. D. Murphy, E. Hendry
Summary: In this paper, a new type of silicon-based metamaterial with a tunable electron-hole lifetime is designed, achieved by periodically patterning a dielectric surface passivation layer. The application of these metamaterials as photomodulators is investigated, with switching times depending on photoexcitation intensity, wafer thickness, and carrier lifetime.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Wipakorn Jevasuwan, Naoki Fukata
Summary: The study simplified the formation of aluminum (Al)-catalyzed silicon nanowires (SiNW) and opened up new possibilities for developing SiNW-based silicon photovoltaic cells.
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
Chemistry, Physical
K. H. Girish
Summary: Perovskite solar cells have made significant progress in efficiency, but are still hindered by surface defects and stability issues. Passivating surface defects with organic halide salts can increase carrier lifetime and improve charge collection efficiency, enhancing the overall performance of the cells.
SURFACES AND INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Sophie L. Pain, Edris Khorani, Tim Niewelt, Ailish Wratten, Marc Walker, Nicholas E. Grant, John D. Murphy
Summary: Incorporation of carrier-selective passivating contacts is crucial for achieving the theoretical power conversion efficiency limit in silicon solar cells. Using plasma-enhanced atomic layer deposition (ALD), we created ultra-thin films that can be chemically enhanced for high-performance contacts. 1 nm thick HfO2 films with negative charge show promising passivation properties, surpassing SiO2 and Al2O3 at equivalent thicknesses. Additional passivation is achieved by applying an Al2O3 capping layer, resulting in a surface recombination velocity (SRV) of 3.5 cm s(-1). Immersion in hydrofluoric acid further improves passivation quality, with stable SRVs < 2 cm s(-1) over 50 days. Chemical enhancement occurs at the dielectric surface and fluorination of the Al2O3 and underlying HfO2 films is observed after just 5 s of HF immersion. The Al2O3 top layer can be thinned down by etching, providing a new route for fabricating highly passivating HfO2-containing nanoscale thin films.
Article
Biochemistry & Molecular Biology
Saltanat B. Ikramova, Zhandos N. Utegulov, Kadyrjan K. Dikhanbayev, Abduzhappar E. Gaipov, Renata R. Nemkayeva, Valery G. Yakunin, Vladimir P. Savinov, Victor Yu Timoshenko
Summary: This study explored the use of silicon nanowires (SiNWs) combined with gold nanoparticles (Au NPs) for surface-enhanced Raman scattering (SERS) of probe molecules. The research found that the filling factor of SiNW arrays controlled the SERS efficiency, with the highest enhancement observed for samples with a porosity of 55%. The results demonstrate the electromagnetic enhancement of SERS through localized surface plasmon resonances in Au-NPs on SiNW surfaces, accompanied by light scattering in the SiNW arrays.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Inorganic & Nuclear
Y. Kim, J. Ko, J. Byun, J. Seo, B. Park
Summary: CdTe-based detectors suffer from the issue of Te-rich surface layers caused by Br etching. These layers act as trapping centers and additional source of charge carriers, which degrade the transport property of charge carriers and increase the leakage current on the detector's surface. To solve this problem, sodium hypochlorite (NaOCl) was introduced as a passivant, and its effect on Cd0.95Mn0.05Te0.98Se0.02 (CMTS) was investigated. The passivation with NaOCl reduced leakage current, compensated defects, improved transport of charge carriers, decreased charge loss, and enhanced the performance of the CMTS detector.
APPLIED RADIATION AND ISOTOPES
(2023)
Article
Nanoscience & Nanotechnology
Aidan P. Conlan, Minh Anh Luong, Pascal Gentile, Grigore Moldovan, Martien Den Hertog, Eva Monroy, David Cooper
Summary: In this study, the structure and electronic properties of Al/SiGe and Al/Si-rich/SiGe axial nanowire heterostructures were characterized using electron beam induced current (EBIC) in a scanning transmission electron microscope. The two heterostructures were found to behave as Schottky contacts with different barrier heights, and the intrinsic semiconductor doping was determined to be n-type. Additionally, it was observed that the silicon-rich double interface presented a lower barrier height compared to the atomically sharp SiGe/Al interface. The Si-rich region delayed the propagation of the depletion region and showed a reduced free carrier diffusion length compared to the SiGe nanowire. These findings demonstrate the significance of scanning transmission electron microscopy EBIC as a powerful method for mapping and quantifying electric fields in micrometer- and nanometer-scale devices.
Article
Optics
A. Bjelajac, M. Gromovyi, E. Sakat, B. Wang, G. Patriarche, N. Pauc, V Calvo, P. Boucaud, F. Boeuf, A. Chelnokov, V Reboud, M. Frauenrath, J. Hartmann, M. El Kurdi
Summary: GeSn alloys are highly promising materials for the integration of CMOS-compatible lasers using Group-IV materials. This study demonstrates room temperature lasing at up to 300 K by utilizing GeSn microdisk resonators fabricated on a GeSn-On-Insulator platform through strain engineering and a thick layer of high Sn content GeSn.
Article
Chemistry, Multidisciplinary
Maxime Legallais, Gauthier Lefevre, Simon Martin, Sebastien Labau, Franck Bassani, Bernard Pelissier, Thierry Baron, Laura Vauche, Cyrille Le Royer, Matthew Charles, William Vandendaele, Marc Plissonnier, Romain Gwoziecki, Bassem Salem
Summary: This article investigates the role of substrate biasing in the passivation of GaN with AlN deposited by PEALD. It is found that applying bias significantly improves GaN passivation compared to standard AlN film deposition. Additionally, the addition of an AlN interlayer deposited with appropriate bias is crucial for positively shifting the flatband voltage of C-V characteristics while maintaining high interface quality.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Physical
Sabria Benrabah, Maxime Legallais, Pascal Besson, Simon Ruel, Laura Vauche, Bernard Pelissier, Chloe Thieuleux, Bassem Salem, Matthew Charles
Summary: This study explores the impact of several wet etchants commonly encountered in the microelectronic industry on the surface chemistry of GaN on silicon. Phosphoric acid treatment is found to significantly modify the surface and enable the recovery of the surface morphology. The study proposes a promising treatment method for the recovery of good quality GaN surfaces after dry etching.
APPLIED SURFACE SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Mohammed Zeghouane, Hadi Hijazi, Franck Bassani, Gauthier Lefevre, Eugenie Martinez, Thierry Luciani, Pascal Gentile, Vladimir G. Dubrovskii, Bassem Salem
Summary: The influence of liquid droplet composition on Sn incorporation in GeSn nanowires (NWs) grown by the vapor-liquid-solid mechanism was investigated. The addition of different elements to the Au catalyst significantly improved the Sn incorporation. The best growth temperature for achieving long untapered NWs was found to be 400 degrees C.
Article
Nanoscience & Nanotechnology
Lama Khalil, Debora Pierucci, Emilio Velez-Fort, Jose Avila, Celine Vergnaud, Pavel Dudin, Fabrice Oehler, Julien Chaste, Matthieu Jamet, Emmanuel Lhuillier, Marco Pala, Abdelkarim Ouerghi
Summary: This study visualizes the presence of a flat band near the Fermi level in the van der Waals WSe2/MoSe2 heterobilayer and confirms the coexistence of different domains with arbitrary twist angles. The strong interlayer hybridization effects are observed, which are further confirmed by complementary micro-Raman spectroscopy measurements.
Article
Nanoscience & Nanotechnology
Jihene Zribi, Debora Pierucci, Federico Bisti, Biyuan Zheng, Jose Avila, Lama Khalil, Cyrine Ernandes, Julien Chaste, Fabrice Oehler, Marco Pala, Thomas Maroutian, Ilka Hermes, Emmanuel Lhuillier, Anlian Pan, Abdelkarim Ouerghi
Summary: By characterizing the electronic properties of a single layer WS1.4Se0.6 alloy, researchers have discovered its unique anisotropic properties. The alloy exhibits a giant unidirectional Rashba spin splitting and in-plane polarization, which could have wide-ranging applications in future electronic, piezoelectric, and spintronic devices.
Article
Chemistry, Multidisciplinary
Yannick Dufil, Marc Dietrich, Dodzi Zigah, Frederic Favier, Said Sadki, Pascal Gentile, Olivier Fontaine
Summary: This study introduces scanning electrochemical microscopy (SECM) as a new technique for in situ characterization and acceleration of degradation processes of conducting polymers, aiming to study the conjugated/conducting polymer-based nanostructured electrodes used for micro-electrochemical energy storage (MEES).
Article
Chemistry, Multidisciplinary
Clement Lausecker, Bassem Salem, Xavier Baillin, Vincent Consonni
Summary: The formation mechanisms of ZnO nanowires from Au seed layers are investigated for different precursor concentrations, leading to variations in the morphological properties. The thermodynamic properties of the chemical bath play a critical role in the formation of ZnO nanowires. This study provides valuable insights for optimizing the morphology of ZnO nanowires for their integration into piezoelectric devices.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Nanoscience & Nanotechnology
Anis Chiout, Cleophanie Brochard-Richard, Laetitia Marty, Nedjma Bendiab, Meng-Qiang Zhao, A. T. Charlie Johnson, Fabrice Oehler, Abdelkarim Ouerghi, Julien Chaste
Summary: A study has found that the frequency of nanomechanical resonators can be effectively tuned at the nanoscale using a suspended MoS2 membrane heated by the Joule effect, with a significantly larger modulation amplitude compared to other approaches. This research is crucial for fully harnessing the potential of two-dimensional materials.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Tarek Spelta, Marc Veillerot, Eugenie Martinez, Denis Mariolle, Roselyne Templier, Nicolas Chevalier, Pedro Fernandes Paes Pinto Rocha, Bassem Salem, Laura Vauche, Berangere Hyot
Summary: This study investigates the effect of inductively coupled plasma reactive ion etching (ICP-RIE) combined with atomic layer etching (ALE) on the Al2O3/GaN interface for MOSc-HEMT devices. The results show an increase of the N/Ga ratio near the interface and the presence of impurities in the etched sample.
SOLID-STATE ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Tarek Spelta, Marc Veillerot, Eugenie Martinez, Nicolas Chevalier, Denis Mariolle, Roselyne Templier, Bassem Salem, Pedro Fernandes Paes Pinto Rocha, Laura Vauche, Sarah Boubenia, Berangere Hyot
Summary: This scientific paper presents a chemical study on different Al2O3/GaN interfaces found in high electron mobility transistors for power electronics. The objective is to overcome the limitation of an oxidized gallium layer that affects the electrical behavior of the semiconductor. The structures were analyzed using ToF-SIMS, M-SIMS, and AFM techniques, and the best experimental conditions were determined.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2023)
Article
Chemistry, Multidisciplinary
Lama Khalil, Cyrine Ernandes, Jose Avila, Adrien Rousseau, Pavel Dudin, Nikolai D. Zhigadlo, Guillaume Cassabois, Bernard Gil, Fabrice Oehler, Julien Chaste, Abdelkarim Ouerghi
Summary: In this study, we demonstrate the stable growth of p-type hexagonal boron nitride (h-BN) by using Mg atoms as substitutional impurities. Our experiments involving micro-Raman spectroscopy, nano-ARPES, and KPFM show that Mg-doping significantly alters the electronic properties of h-BN. The Mg dopants shift the valence band maximum and result in a reduced Fermi level difference between pristine and Mg-doped h-BN crystals. This research establishes Mg-doping as a promising method for high-quality p-type doped h-BN films, which are crucial for applications in deep ultraviolet LEDs and wide bandgap optoelectronic devices.
NANOSCALE ADVANCES
(2023)
Article
Materials Science, Multidisciplinary
Quang Chieu Bui, Gustavo Ardila, Herve Roussel, Carmen Jimenez, Isabelle Gelard, Odette Chaix-Pluchery, Xavier Mescot, Sarah Boubenia, Bassem Salem, Vincent Consonni
Summary: The research investigates the impact of O-2 gas and DEZn solution flow rates on properties of ZnO thin films, finding that the piezoelectric amplitude of ZnO thin films is significantly affected by the O-2/DEZn flow rate ratio, with Zn-polarity domains exhibiting a larger amplitude than O-polarity domains. Additionally, a comprehensive description of the formation process through different regimes is gained.
MATERIALS ADVANCES
(2022)
