Article
Nanoscience & Nanotechnology
S. Levcenko, B. Teymur, D. B. Mitzi, T. Unold
Summary: Characterization of radiative transitions in trigonal Cu2BaSnS4 was experimentally studied via temperature and excitation intensity dependent photoluminescence measurements, revealing the contributions of free exciton, bound exciton, donor-acceptor-pair recombination, and free-to-bound transition. The activation energies and temperature shift for the radiative transitions were determined, with optical phonons playing a significant role in the energy shift of free exciton recombination above 90 K.
Article
Physics, Multidisciplinary
Peizhi Du, Daniel Egana-Ugrinovic, Rouven Essig, Mukul Sholapurkar
Summary: The study discusses various low-energy backgrounds affecting sub-GeV dark matter searches, with a focus on Cherenkov radiation, transition radiation, and recombination-generated photons. Detailed analyses of these backgrounds at current and planned detectors highlight the importance of design strategies in mitigating the impact of these backgrounds on dark matter detection sensitivity. Additionally, the study points out that future experiments aiming to detect dark matter via scintillation or phonon signals may face significant background challenges from Cherenkov radiation, transition radiation, and recombination.
Article
Physics, Fluids & Plasmas
Domen Paul, Miran Mozetic, Rok Zaplotnik, Jernej Ekar, Alenka Vesel, Gregor Primc, Denis Donlagic
Summary: The recombination of neutral oxygen atoms on oxidized nickel samples in low-pressure weakly ionized oxygen plasma was experimentally studied. The recombination coefficient was determined in the afterglow chamber using the Sorli method to measure the density of oxygen atoms and calorimetry to determine the coefficient. The recombination coefficient exhibited an inverse square root relationship with pressure and an exponential relationship with sample temperature. Systematic measurements at various pressures and temperatures yielded empirical formulas that were qualitatively explained by recombination kinetics.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
Patrik Scajev, Algirdas Mekys, Liudvikas Subacius, Sandra Stanionyte, Darius Kuciauskas, Kelvin G. Lynn, Santosh K. Swain
Summary: In this study, the dependence of recombination rate on excitation and temperature in CdTe was investigated using advanced CdTe single crystals and electro-optical measurements. Different recombination defects and temperature dependencies of surface recombination rate were revealed.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
Veronique Brousseau-Couture, Xavier Gonze, Michel Cote
Summary: The electronic structure of semiconductors and insulators is influenced by ionic motion through electron-phonon interaction, resulting in temperature-dependent band gap energies and zero-point renormalization (ZPR) at absolute zero temperature. The Frohlich model explains the significant contribution of nonadiabatic interaction between an electron and the macroscopic electrical polarization created by an optical longitudinal phonon mode. SOC modifies the bare electronic structure and leads to a decrease in ZPR, driven by the valence band edge and the modification of the hole effective masses. The inclusion of SOC in the generalized Frohlich model shows the unchanged predominance of nonadiabatic effects on the ZPR of polar materials.
Article
Optics
Dongke Li, Jiaming Chen, Teng Sun, Yangyi Zhang, Jun Xu, Wei Li, Kunji Chen
Summary: Phosphorus/boron co-doping in Si quantum dots/SiO2 multilayers enhances subband light emission, with increasing B co-doping ratio resulting in improved emission intensity nearly two orders of magnitude stronger than solely P-doped samples. This enhancement is attributed to B dopants passivating surface dangling bonds, leading to suppressed phosphorus-related deep level emission and appearance of emission centered around 1400 nm in high B co-doping ratios.
Article
Energy & Fuels
Cyril Leon, Pierre Saint-Cast, Andreas Fell, Johannes M. Greulich, Stefan Rein
Summary: The robustness of a method called Fourier-transform photoluminescence (FTPL) is investigated to determine the recombination current-density (J0,met) under the front metallization fingers of silicon solar cells. The method uses a voltage-calibrated photoluminescence imaging setup and does not require any dedicated sample preparation. The results show that the FTPL method can differentiate solar cells that have undergone different metallization conditions and provides similar results compared to other characterization techniques.
Article
Physics, Applied
Sorren Warkander, Junqiao Wu
Summary: This study explores the dominant techniques in laser-based thermal measurement and presents a method for measuring semiconductor samples without the need for a metal transducer. The feasibility and accuracy of this method are demonstrated through experimental data.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Domen Paul, Miran Mozetic, Rok Zaplotnik, Jernej Ekar, Alenka Vesel, Gregor Primc, Denis Donlagic
Summary: Calorimetry is commonly used for plasma characterization, but its accuracy is tied to the recombination coefficient, which depends on surface effects. Surface effects also govern the kinetics in advanced methods such as atomic layer oxidation and functionalization. The recombination coefficient of oxidized cobalt surface was studied systematically, showing a monotonic increase with decreasing pressure and increasing temperature.
Article
Energy & Fuels
Shuai Nie, Robert Lee Chin, Arman Mahboubi Soufiani, Torbjorn Mehl, Felix Theska, Nima Haghdadi, Sophie Primig, Catherine Chan, Thorsten Trupke, Ziv Hameiri
Summary: This study assesses the influence of different processes on the temperature-dependent electrical performance of solar cells using temperature-dependent photoluminescence imaging measurements. It finds that the height of the wafer within the ingot impacts the response of the temperature coefficient to different fabrication processes. Advanced hydrogenation is found to reduce the temperature sensitivity. Crystallographic defects are found to be the least temperature sensitive regions, possibly due to impurities decorating them.
PROGRESS IN PHOTOVOLTAICS
(2022)
Article
Materials Science, Multidisciplinary
Dhiman Nag, Shreekant Sinha, Ritam Sarkar, Ray-Hua Horng, Apurba Laha
Summary: The study investigates the impact of self-heating on the performance of InGaN green LEDs, revealing that Auger recombination dominates at high forward bias, and the increase in reverse leakage current at high temperatures is attributed to carriers escaping due to adequate thermal energy.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Deepu Kumar, Rahul Kumar, Mahesh Kumar, Pradeep Kumar
Summary: This study investigates the dynamics of excitons/trions and their coupling with phonons and charge carriers in vertically and horizontally aligned MoS2. The results show that the dynamics of excitons/trions and their coupling are more affected in vertically aligned MoS2. Additionally, interlayer coupling has significant effects on both systems, as observed through temperature-dependent valence band splitting and trion binding energy. The intensity of the trion band also exhibits significant thermal quenching compared to the exciton bands.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Physics, Applied
Nian Xie, Weijia Fan, Meng Tang, Chang Pan, Wei Zhu, Shiming Zhou, Xuepeng Qiu
Summary: We investigate the spin Hall mechanism and spin-orbit torque (SOT) efficiency in Ta/CoFeB/MgO heterostructures by controlling the Ta crystalline phases. The beta phase Ta exhibits a negative temperature coefficient of resistivity and shows a significant contribution of skew scattering to the spin Hall effect. Despite higher resistivity, beta Ta has lower power consumption than (alpha+beta) Ta phase, making it a superior spin-orbit material. These findings provide valuable insights for manipulating SOT and SHE mechanisms through crystalline phase engineering.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Bruno P. Falcao, Joaquim P. Leitao, Lidia Ricardo, Hugo Aguas, Rodrigo Martins, Rui N. Pereira
Summary: This study clarifies the dominant electron-hole recombination mechanisms and the origin of light emission in Si-NPs with different forms of surface passivation. The research shows that at low excitation powers, recombination of photo-carriers is dominated by monomolecular channels via defect states, while at high excitation powers, electron-hole bimolecular recombination dominates. The sensitivity of H-terminated Si-NPs to photo-oxidation and its consequences for Si-NP applications are discussed, with photo-oxidation described within the Cabrera-Mott chemical reactions theory.
APPLIED MATERIALS TODAY
(2021)
Article
Energy & Fuels
T. Niewelt, B. Steinhauser, A. Richter, B. Veith-Wolf, A. Fell, B. Hammann, N. E. Grant, L. Black, J. Tan, A. Youssef, J. D. Murphy, J. Schmidt, M. C. Schubert, S. W. Glunz
Summary: This study characterizes and optimizes next-generation silicon solar cell concepts by accurately assessing intrinsic recombination in crystalline silicon. By fabricating high-quality silicon sample sets and considering reabsorption effects, the researchers were able to extract the lifetime limitation due to Auger recombination. The revised fundamental limiting power conversion efficiency for single-junction crystalline silicon solar cells provides greater accuracy and alignment with actual recombination processes in silicon-based photovoltaics.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Energy & Fuels
Anh Dinh Bui, Naeimeh Mozaffari, Thien N. Truong, The Duong, Klaus J. Weber, Thomas P. White, Kylie R. Catchpole, Daniel Macdonald, Hieu T. Nguyen
Summary: A contactless, imaging-based procedure was reported to spatially resolve electronic properties of PSCs, including iV(oc), n(id), and E-A, using illumination intensity and temperature-dependent photoluminescence. The illumination intensity and temperature dependence allowed for the extraction of electronic parameters and investigation of their changes on fully and partially fabricated devices.
PROGRESS IN PHOTOVOLTAICS
(2022)
Article
Oncology
Hieu Trong Nguyen, Kien Hung Do, Nguyen Ba Le, Thang Tran
Summary: This study evaluated the efficacy and safety of the paclitaxel, carboplatin, and capecitabine (TCX) regimen in patients with advanced gastric cancer. The results showed that the TCX regimen provided good survival outcomes and had a favorable safety profile.
CANCER MANAGEMENT AND RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
G. D. Tabi, H. T. Pham, H. Zhan, D. Walter, A. O. Mayon, J. Peng, T. Duong, Mohammed M. Shehata, H. Shen, L. Duan, N. Mozaffari, L. Li, M. A. Mahmud, H. T. Nguyen, K. Weber, K. R. Catchpole, T. P. White
Summary: The study investigates the doping of lithium iodide (LiI) into mixed-cation mixed-halide (MCMH) perovskites, which improves the film morphology and optoelectronic properties of the devices. The optimized Li-doped devices achieve higher power conversion efficiency and minimized current-voltage hysteresis compared to undoped devices. The study also reveals the changes in ionic properties and transient response with excessive LiI doping.
MATERIALS TODAY PHYSICS
(2022)
Article
Chemistry, Physical
Md Arafat Mahmud, Jianghui Zheng, Shi Tang, Chwenhaw Liao, Guoliang Wang, Jueming Bing, Tik Lun Leung, Anh Dinh Bui, Hongjun Chen, Jianpeng Yi, Stephen P. Bremner, Hieu T. Nguyen, Anita W. Y. Ho-Baillie
Summary: State-of-the-art perovskite-perovskite tandem solar cells use a water-based PEDOT:PSS hole transport layer in the low bandgap subcell, but its use is limited due to moisture sensitivity and insulating property. We overcome this limitation by using a water-free and PSS-free PEDOT-based hole transport layer, achieving higher efficiency and reproducibility in perovskite-perovskite tandems.
ACS ENERGY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Xuan Minh Chau Ta, Thi Kim Anh Nguyen, Anh Dinh Bui, Hieu T. T. Nguyen, Rahman Daiyan, Rose Amal, Thanh Tran-Phu, Antonio Tricoli
Summary: Photoelectrochemical water splitting is a promising approach to produce green hydrogen using solar energy. However, the lack of efficient photoanodes to catalyze the water photooxidation reaction remains a challenge. In this study, nanostructured FeWO4 photoanodes were synthesized on a fluorine doped tin oxide glass substrate via a scalable and ultra-fast flame synthesis route. The optimized FeWO4 photoanode with a bandgap of 1.82 eV and a FeOOH/NiOOH co-catalyst coating showed improved water photooxidation performance and good photostability, providing insights for the engineering of small band-gap catalysts for various photoelectrochemical applications.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Nanoscience & Nanotechnology
Jiali Wang, Sieu Pheng Phang, Christian Samundsett, Zhuofeng Li, Thien N. Truong, Jie Yang, Zhao Wang, Peiting Zheng, Xinyu Zhang, Hieu T. Nguyen, Daniel Macdonald, Josua Stuckelberger
Summary: In this study, high-quality localized phosphorus-doped polycrystalline silicon passivating contacts with nanoscale poly-Si film on an ultrathin SiOx layer were fabricated using an inkjet printing technique. The effects of printer settings, dopant concentration, and annealing temperature on the contact performance were investigated. Good surface passivation was achieved with optimized conditions, and after hydrogenation treatment, the implied open-circuit voltage was further improved.
ACS APPLIED NANO MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Hieu T. T. Nguyen, Md. Noor-A-Rahim, Yong Liang Guan, Dirk Pesch
Summary: This paper analyzes the impact of big vehicle shadowing on V2V communications and proposes a beamforming-based signal reception technique to mitigate packet collisions caused by hidden nodes. Three relaying schemes are also proposed to improve the V2V message dissemination performance.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Materials Science, Coatings & Films
Gabriel Bartholazzi, M. M. Shehata, Daniel H. Macdonald, Lachlan E. Black
Summary: In this study, Cu2O thin films were successfully deposited using copper acetylacetonate as a precursor and a combination of water and oxygen as reactants at 200 degrees C. The deposited Cu2O film was found to be polycrystalline and uniform, with specific bandgap values.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Energy & Fuels
Mohamed M. Shehata, Thien N. Truong, Rabin Basnet, Hieu T. Nguyen, Daniel H. Macdonald, Lachlan E. Black
Summary: Impedance spectroscopy is a powerful characterization technique that has not been widely applied to c-Si solar cells. This study demonstrates the application of IS technique to a high-efficiency c-Si solar cell and shows that it can distinguish different components and determine lifetimes. The findings suggest that IS is a promising technique for exploring dynamic properties of high-efficiency c-Si solar cells.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Chemistry, Physical
Shuwen Cheng, Zhehao Sun, Kang Hui Lim, Ary Anggara Wibowo, Tianxi Zhang, Tao Du, Liying Liu, Hieu T. T. Nguyen, Gang Kevin Li, Zongyou Yin, Sibudjing Kawi
Summary: By stacking/constructing an ultrathin dual-defective two-dimensional (2D)/2D Z-scheme heterojunction with growing functional anionic vacancies onto both reductive and oxidative components of the Z-scheme, this work successfully overcomes the challenges of charge separation and redox capacities, achieving excellent photoactivity in CO2 reduction. The N-vacancy-rich g-C3N4 exhibits active and selective photoreduction ability, accompanied with oxidation reactions from O-vacancy-rich BiOCl. This work provides an effective adaptable dual-defect engineering on 2D/2D heterojunctions to enhance CO2 photoreduction.
Article
Physics, Applied
Boqing Liu, Tanju Yildirim, Elena Blundo, Domenico de Ceglia, Ahmed Raza Khan, Zongyou Yin, Hieu T. Nguyen, Giorgio Pettinari, Marco Felici, Antonio Polimeni, Yuerui Lu
Summary: In this study, large pressurized monolayer TMD domes were fabricated using proton irradiation, and their SHG performance was comprehensively investigated. The results showed that the intensity of SHG was effectively enhanced by around two orders of magnitude at room temperature. This giant enhancement was attributed to the distinct separation distance induced by capped pressurized gas and the hemi-spherical morphology, which enabled constructive optical interference. Moreover, the unique divergent strain field in TMD domes promoted the first experimental study on the anisotropic nonlinear optical behavior based on biaxial strain conditions.
APPLIED PHYSICS REVIEWS
(2023)
Article
Materials Science, Multidisciplinary
Ary Anggara Wibowo, Mike Tebyetekerwa, Anh Dinh Bui, Thien N. Truong, Sandra Saji, Felipe Kremer, Zhongshu Yang, Zongyou Yin, Yuerui Lu, Daniel Macdonald, Hieu T. Nguyen
Summary: In this study, a method for growing large-area, high-quality MoSe2 monolayers and MoSe2-WSe2/WSe2-MoSe2 lateral heterostructures using molten salt-based chemical vapor deposition (CVD) is reported. The effects of different catalysts on the growth and optoelectronic quality of the materials are investigated, and it is found that molten salt catalysts support high-quality growth of MoSe2 monolayers and WSe2-MoSe2 lateral heterostructures.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Computer Science, Information Systems
Khiem H. Le, Tuan V. V. Tran, Hieu H. H. Pham, Hieu T. T. Nguyen, Tung T. Le, Ha Q. Q. Nguyen
Summary: Recent years have seen tremendous growth in computer-aided diagnosis systems based on machine learning algorithms for anomaly detection in medical images. However, the reliability of these algorithms is heavily dependent on the quality of labels, as the subjectivity of a single annotator can introduce uncertainty. To address this issue, aggregating labels from multiple radiologists of varying expertise levels has been established. This paper proposes a simple yet effective approach to enhance the efficiency of neural networks in abnormal detection tasks by estimating hidden labels from multiple annotations. The proposed approach is evaluated on simulated and real-world medical imaging datasets, showing superior performance compared to baselines that do not consider inter-annotator disagreements.
Article
Chemistry, Physical
Hang Yin, Zhehao Sun, Kaili Liu, Ary Anggara Wibowo, Julien Langley, Chao Zhang, Sandra E. Saji, Felipe Kremer, Dmitri Golberg, Hieu T. Nguyen, Nicholas Cox, Zongyou Yin
Summary: This study reveals the synergy between defection sites on catalyst surfaces and hard metal nanoparticles, and their importance in enhancing photocatalytic activity and maintaining selectivity.
NANOSCALE HORIZONS
(2023)
