Article
Nanoscience & Nanotechnology
I. M. Costa, E. P. de Araujo, A. N. Arantes, M. A. Zaghete, A. J. Chiquito
Summary: The persistent photoconductivity effect in SnO(2) nanostructures was studied through a comparative study of electronic transport measurements on network and single devices. It was found that nanowire-nanowire junctions play a fundamental role in the device behavior, with the decay time of nanowire network significantly lower than single nanowires. The PPC effect was directly related to the amount of oxygen present in the environment and destroyed with increasing temperature, and was interpreted based on the surface effect of capture/emission of electrons by surface states.
Article
Materials Science, Ceramics
Anu Katiyar, Nishant Kumar, R. K. Shukla, Anchal Srivastava
Summary: This study synthesized undoped, doped, and co-doped vertically aligned zinc oxide nanorods (NRs) using a sonicated sol-gel immersion method and investigated the structural, morphological, optical, and photoconductivity properties of NRs with different dopants. The results showed that the incorporation of Fe improved the growth of NRs, while the incorporation of Ag had a detrimental effect. Co-doping enhanced the light harvesting efficiency and reduced the persistent photoconductivity.
CERAMICS INTERNATIONAL
(2022)
Article
Nanoscience & Nanotechnology
Peter M. Wojcik, Lyndon D. Bastatas, Negar Rajabi, Pavel Bakharev, David N. McIlroy
Summary: This study investigates the electrical and optoelectronic properties of nanometer-sized ZnO structures, highlighting the significant influence of native point defects on these properties. By fabricating an electronic device to characterize the ZnO layer, it is found that the energy of excitation sources and the trapping of electrons and holes in defect levels within the bandgap have a major impact on the photocurrent characteristics. The paper provides physical models to describe the behavior of photocurrent under different excitation sources and proposes a phenomenological model to explain the dependence of saturation photocurrent on excitation intensity.
Article
Chemistry, Physical
Shuai Zhao, Jiamin Sun, Yanxue Yin, Yanan Guo, Dong Liu, Chengcheng Miao, Xiao Feng, Yiming Wang, Mingsheng Xu, Zai-xing Yang
Summary: The research successfully prepared GeS nanowires with controlled sulfur-rich shell, diameter, and length using a simple chemical vapor deposition method. By studying the composition and growth process of the sulfur-rich shell, the crucial role of NPC effect in optoelectronic devices was revealed. The carefully designed and controlled growth of an NPC-effect-caused shell is essential for future optoelectronic applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Meriem Aloui, Loubna Mentar, Abdelkrim Beniaiche, Amor Azizi
Summary: In this paper, the influence of current density on ZnO nanosheets formed by electrochemical deposition and the effect of mode on ZnO nanosheets and nanowires were studied. Current density had significant effects on the properties of ZnO nanosheets, while the mode transformation had important impacts on the crystallization, optical transmittance, and carrier density of ZnO nanosheets and nanowires.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Physics, Applied
M. J. da Silva, L. M. B. Vargas, M. P. F. de Godoy, K. Bolanos, D. A. W. Soares, S. de Castro, M. L. Peres
Summary: The Shubnikov-de Haas oscillation was observed in a polycrystalline ZnO/CdO heterostructure grown on a silicon substrate using spray pyrolysis technique at temperatures below 6 K. Analysis of the quantum oscillations yielded information on the cyclotronic effective mass, 2D carrier concentration, and thickness of the two-dimensional electron gas at the interface. Results indicate successful formation of a two-dimensional electron gas at the ZnO/CdO interface.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Analytical
Kamran Syed, Niksa Krstulovic, Juan Casanova-Chafer, Eduard Llobet, Frank Guell, Paulina R. Martinez-Alanis, Marijan Marcius, Ekaterina Shagieva, Davor Ristic, Hrvoje Gebavi, Nikola Baran, Mile Ivanda
Summary: ZnO films were prepared using pulsed laser deposition with different background atmospheres and their gas-sensing properties and microstructure characteristics were investigated. The films grown in an argon atmosphere showed a highly textured hexagonal crystalline structure with the c-axis perpendicular to the substrate plane. The vacuum-grown films exhibited better growth in the (100) plane. Raman and PL spectroscopy confirmed the presence of defects in both types of films. Gas-sensing experiments revealed that the vacuum-grown films had a higher response to nitrogen dioxide (NO2) at ppb levels compared to the argon-grown films, which was attributed to differences in crystallinity, microstructure, and defect type.
SENSORS AND ACTUATORS B-CHEMICAL
(2023)
Article
Materials Science, Multidisciplinary
Baoshi Qiao, Zhenzhong Zhang, Xiuhua Xie, Binghui Li, Xing Chen, Haifeng Zhao, Kewei Liu, Lei Liu, Dezhen Shen
Summary: A new type of photoconductive gain with controllable response speed is discovered in Ga2O3 photodetector, attributed to the forming and breaking of conductive filaments composed of oxygen vacancies. UV illumination has been shown to accelerate the formation of the filament, providing a direction for the combination of speed-control and high sensitivity for photodiodes.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Artem Chizhov, Marina Rumyantseva, Nikolay Khmelevsky, Andrey Grunin
Summary: In this study, colloidal perovskite nanocrystals were used to enhance the photoconductivity of nanocrystalline ZnO films. The synthesis process of the nanocrystalline ZnO and perovskite nanocrystals was carefully controlled, and the enhanced photoconductivity and the maximum photoconductivity values were observed. The structure, morphology, and other properties of the synthesized nanocrystals were also investigated, and the potential applications of the results were discussed.
Article
Physics, Multidisciplinary
Xingfei Zhang, Yiyun Zhang, Dong Pan, Xiaoyan Yi, Jianhua Zhao, Jinmin Li
Summary: One-dimensional indium arsenide nanowire photodetectors with a metal-semiconductor-metal structure exhibit strong negative photoconductive effects and high gain, showing potential applications in visible/near-infrared light communication.
FRONTIERS IN PHYSICS
(2021)
Article
Physics, Applied
C. A. Figueroa, M. C. Zapata, G. Bridoux, J. Ferreyra, L. Patrone, L. Malatto, J. Guimpel, G. Nieva, V Runco Leal, C. Navarro, M. Villafuerte
Summary: The work reported on the fabrication and characterization of a field effect transistor based on a ZnO/MgO bilayer with a top-gate configuration. X-ray diffraction patterns showed epitaxial growth of ZnO and MgO films. The intrinsic properties of transparent conducting oxides were shown to determine key parameters of a FET device.
APPLIED PHYSICS LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Tianyi Gao, Leyan Nian, Li Jin, Haoying Sun, Tingting Zhang, Jiangfeng Yang, Zhengbin Gu, Luming Peng, Yuefeng Nie
Summary: Researchers reported a giant switchable persistent photoconductivity (PPC) in SrTiO3 materials reduced by soft chemistry. Via nuclear magnetic resonance measurements, it was found that this unusual PPC is driven by the generation of excess carriers accompanied with a configuration evolution of the incorporated hydrogen from hydridic H-O(+) to protic H-i(+) upon illumination. This work demonstrates a giant switchable PPC transition in soft chemistry reduced perovskite oxides, providing a new platform for pursuing high performance sensors and nonvolatile optoelectronic memory devices.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
Joel Y. Y. Loh, Moein Shayegannia, Nazir P. Kherani
Summary: The study shows that doping with bismuth as a substitution of indium can significantly increase the CO production rate in the reverse water gas shift reaction under illumination, enhancing the photo-thermalization effect. High-doped In2O3-x(OH)(y) materials exhibit a longer persistent CO yield post-illumination, with increased yield, while low-doped and undoped systems have shorter duration and lower yield. Additionally, undoped systems show a slower decay trend in photocurrent for 1-2 hours, while high-doped systems exhibit a decay trend of more than 2 hours.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Chemistry, Analytical
Vo Thanh Duoc, Chu Manh Hung, Hugo Nguyen, Nguyen Van Duy, Nguyen Van Hieu, Nguyen Duc Hoa
Summary: The grafted structures between SnO2 and ZnO nanowires were achieved through a two-step growth process, showing promising sensitivity for NO2 gas sensing.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Chemistry, Multidisciplinary
Pengshan Xie, Xu Chen, Zixin Zeng, Wei Wang, You Meng, Zhengxun Lai, Quan Quan, Dengji Li, Weijun Wang, Xiuming Bu, Sai-Wing Tsang, SenPo Yip, Jia Sun, Johnny C. C. Ho
Summary: This paper proposes large-scale artificial synaptic device arrays based on organic molecule-nanowire heterojunctions with tunable photoconductivity, which can mimic and realize the functions of visual systems. These devices have tunable photoconductivity and response to multiple wavelengths, which can improve the recognition rate of neural networks.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Shiva Choupanian, Alessandro Nagel, Wolfhard Moeller, Claudia Pacholski, Carsten Ronning
Summary: This study investigates the morphology changes of silver nanoparticles under ion irradiation. Hemispherical nanoparticles become conical and eventually disappear at higher ion energies, while under lower ion energies, new particles reappear with various structures.
Article
Materials Science, Multidisciplinary
M. Novakovic, M. Popovic, P. Noga, D. Vana, C. Ronning
Summary: This study investigates the effects of pure silver and silver/gold co-implanted TiN thin films on their optical properties, significantly reducing optical losses and approaching the optical performance of pure gold. This optical tuning of TiN opens up new possibilities for its implementation in plasmonic applications.
Article
Physics, Fluids & Plasmas
E. Eftekhari-Zadeh, M. S. Bluemcke, Z. Samsonova, R. Loetzsch, I. Uschmann, M. Zapf, C. Ronning, O. N. Rosmej, D. Kartashov, C. Spielmann
Summary: In this study, the absorption of laser energy in bulk and different morphology nanowire arrays interacting with relativistically intense, ultra-high temporal contrast femtosecond laser pulses was experimentally measured. The results showed an almost twofold enhancement of absorption in nanowire arrays compared to bulk samples, and this enhanced absorption was confirmed by high-resolution x-ray emission spectroscopy.
PHYSICS OF PLASMAS
(2022)
Proceedings Paper
Physics, Atomic, Molecular & Chemical
K. Bharuth-Ram, D. Naidoo, V Adoons, C. Ronning
Summary: In this study, a GaN thin film grown on sapphire substrate was implanted with Fe-57 and Fe-56 ions to induce lattice damage. The results showed a significant increase in the spectral component of Fe-Ga and a decrease in the Fe lattice damage component during high-temperature annealing.
HYPERFINE INTERACTIONS
(2022)
Article
Chemistry, Physical
Shiva Choupanian, Wolfhard Moller, Martin Seyring, Carsten Ronning
Summary: This study experimentally demonstrates channeling of low-energy ions in crystalline nanoparticles, which differs from conventional high-energy ion irradiation. Channeling has a significant impact on ion transport in crystals and is relevant for focused ion beam (FIB) applications. Therefore, it is recommended not to solely rely on standard Monte-Carlo algorithms for predicting ion distribution depths in amorphous materials.
Article
Materials Science, Multidisciplinary
Lukas Peters, Christoph Margenfeld, Jan Krugener, Carsten Ronning, Andreas Waag
Summary: The presence of carbon impurities in AlN was believed to be the main cause of the absorption at 265 nm. However, this study revealed that the intrinsic nitrogen-vacancy defect V-N plays a crucial role in the absorption. This finding is significant for further improvement of UV-LEDs.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Optics
Daniel Repp, Angela Barreda, Francesco Vitale, Isabelle Staude, Ulf Peschel, Carsten Ronning, Thomas Pertsch
Summary: Semiconductor nanowire lasers can have their lasing threshold modified by their environment, and using metallic substrates can access low-volume Surface-Plasmon-Polariton (SPP) modes and describe mode competition in nanowire lasers. The study found that an aluminum substrate decreases the lasing threshold for ZnO nanowire lasers, while a silver substrate increases the threshold compared to a dielectric substrate. These findings allow for predictions about the interaction between planar metals and semiconductor nanowires, guiding future improvements in highly-integrated laser sources.
Article
Chemistry, Multidisciplinary
Christian T. Plass, Valentina Bonino, Maurizio Ritzer, Lukas R. Jager, Vicente Rey-Bakaikoa, Martin Hafermann, Jaime Segura-Ruiz, Gema Martinez-Criado, Carsten Ronning
Summary: The dynamics of color centers in quantum technology are influenced by the local environment, and a combined approach of X-ray fluorescence analysis and X-ray excited optical luminescence (XEOL) was used to study this relationship. The simultaneous acquisition of data revealed compositional and functional variations at the nanoscale, demonstrating the extraordinary capabilities of these techniques. The findings on cobalt doped zinc oxide nanowires showed an anticorrelation between the band edge emission of the zinc oxide host and the intra-3d cobalt luminescence, indicating two competing recombination paths. Time-resolved XEOL measurements also revealed two exponential decays of the cobalt luminescence, with the fast decay attributed to a recombination cascade within the cobalt atom.
Article
Physics, Applied
F. Vitale, D. Repp, T. Siefke, U. Zeitner, U. Peschel, T. Pertsch, C. Ronning
Summary: In this study, a mode selection scheme based on distributed feedback was proposed to achieve quasi-single mode lasing action in plasmonic nanowires. The orientation of the nanowire on the grating was found to affect the emission spectrum, with an additional peak emerging when the nano-cavity was perpendicular to the ridge direction. This peak was attributed to a hybrid mode dominating the mode competition and supported by localized plasmon polaritons on the metal grating ridges.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
M. Popovic, M. Novakovic, D. Vana, C. Ronning, D. Jugovic, V. Rajic, P. Noga
Summary: In this study, sequential implantation of gold and silver ions with varying ion fluence, as well as subsequent annealing, were used to modify the optical and plasmonic properties of TiN thin films and correlate them with their structural properties. The implanted films showed reduced metallicity and lower losses compared to the as-deposited film, while subsequent annealing partially recovered the destroyed structure and improved the metallic properties. By optimizing the implantation fluence of silver ions, TiN films with desirable optical performances were obtained.
Article
Materials Science, Multidisciplinary
Lukas Peters, Hendrik Spende, Stefan Wolter, Christoph Margenfeld, Carsten Ronning, Tobias Voss, Andreas Waag
Summary: In this study, carbon-implanted and high-temperature annealed AlN layers were analyzed using cathodoluminescence spectroscopy. Donor-acceptor pair transitions between carbon and oxygen impurities were identified. The presence of oxygen led to absorption in the deep UV range, while carbon was responsible for an absorption band at around 265 nm. The findings were supported by temperature- and power-dependent emission energy shifts and luminescence transients.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
Nicholas A. Gusken, Ming Fu, Maximilian Zapf, Michael P. Nielsen, Paul Dichtl, Robert Roeder, Alex S. Clark, Stefan A. Maier, Carsten Ronning, Rupert F. Oulton
Summary: Since Purcell's seminal report 75 years ago, electromagnetic resonators have been used to control light-matter interactions to make brighter radiation sources and unleash unprecedented control over quantum states of light and matter. In this letter, the authors report a strong radiative emission rate enhancement of Er3+-ions across the telecommunications C-band in a single plasmonic waveguide based on the Purcell effect. The waveguide uses a reverse nanofocusing approach to efficiently enhance, extract, and guide emission from the nanoscale to a photonic waveguide, while keeping losses at a minimum.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Robert Wonneberger, Gloria Kirste, Martin Seyring, Martin Hafermann, Carsten Ronning, Maximilian Schaal, Felix Otto, Torsten Fritz, Andreas Undisz
Summary: Understanding the growth mechanism of oxide layer on 316 L requires knowledge of reaction front position, oxide phase formation, and elements diffusion paths. By using Mn as a tracer in a new experimental approach, essential information of the early stages of oxidation up to 600 °C is obtained. The study suggests a previously undocumented role of Cr valence state during oxide growth, as Cr6+ is detected at 600 °C.
Article
Materials Science, Multidisciplinary
Alexander Koch, Hongyan Mei, Jura Rensberg, Martin Hafermann, Jad Salman, Chenghao Wan, Raymond Wambold, Daniel Blaschke, Heidemarie Schmidt, Jurgen Salfeld, Sebastian Geburt, Mikhail A. A. Kats, Carsten Ronning
Summary: This study demonstrates the heavy and hyper doping of ZnO with gallium (Ga) ions using a focused ion beam (FIB) system combined with post-implantation laser annealing. The ion implantation allows for the incorporation of impurities with high concentrations, while the laser annealing process activates the dopants close to or beyond the solid-solubility limit of Ga in ZnO. Heavy doped ZnO:Ga with a free-carrier concentration of approximately 10^(21) cm^(-3) and a plasma wavelength of 1.02 μm is achieved, making it a promising plasmonic material for applications in the near infrared regime.
ADVANCED PHOTONICS RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Edwin Eobaldt, Francesco Vitale, Maximilian Zapf, Margarita Lapteva, Tarlan Hamzayev, Ziyang Gan, Emad Najafidehaghani, Christof Neumann, Antony George, Andrey Turchanin, Giancarlo Soavi, Carsten Ronning
Summary: Mixed-dimensional hybrid structures are promising building blocks for controlling and modulating lasers at the nanoscale. Hybridization of ZnO nanowires with MoS2 monolayers allows for tuning the lasing wavelength at the nanoscale.
