Article
Materials Science, Multidisciplinary
Laya Dejam, Slawomir Kulesza, Jamshid Sabbaghzadeh, Atefeh Ghaderi, Shahram Solaymani, Stefan Talu, Miroslaw Bramowicz, Mitra Amouamouha, Amir Hossein Salehi Shayegan, Amir Hossein Sari
Summary: In this study, thin films of undoped ZnO, ZnO doped with Al, ZnO doped with Cu, and co-doped ZnO with Al and Cu were deposited on quartz substrates using RF sputtering. The samples were investigated for their advanced fractal features, crystalline structure, and optical properties. The results showed that the films had different morphologies and transmission spectra, with the co-doped sample exhibiting the highest transparency in the visible region and a desirable band gap.
RESULTS IN PHYSICS
(2023)
Article
Multidisciplinary Sciences
Lucas Schneider, Philip Beck, Levente Rozsa, Thore Posske, Jens Wiebe, Roland Wiesendanger
Summary: Spin chains proximitized by s-wave superconductors are predicted to enter a mini-gapped phase with topologically protected Majorana modes (MMs) localized at their ends. However, the presence of non-topological end states mimicking MM properties can hinder their unambiguous observation. Here, we report on a direct method to exclude the non-local nature of end states via scanning tunneling spectroscopy by introducing a locally perturbing defect on one of the chain's ends. We apply this method to particular end states observed in antiferromagnetic spin chains within a large minigap, thereby proving their topologically trivial character. A minimal model shows that, while wide trivial minigaps hosting end states are easily achieved in antiferromagnetic spin chains, unrealistically large spin-orbit coupling is required to drive the system into a topologically gapped phase with MMs. The methodology of perturbing candidate topological edge modes in future experiments is a powerful tool to probe their stability against local disorder. Spin chains on superconductors have been studied as a possible venue for zero-energy Majorana bound states at the ends of the chain. Here, the authors observe localized end states in antiferromagnetic chains, but rule out a Majorana origin of these states by perturbing them with local defects.
NATURE COMMUNICATIONS
(2023)
Article
Quantum Science & Technology
Arthur Leis, Michael Schleenvoigt, Vasily Cherepanov, Felix Luepke, Peter Schueffelgen, Gregor Mussler, Detlev Gruetzmacher, Bert Voigtlaender, F. Stefan Tautz
Summary: This study investigated the transport properties of (Bi0.16Sb0.84)2Te3 films across a quantum phase transition, revealing an exponential drop in conductivity below the critical thickness, indicating the presence of spin-conserving backscattering.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Chemistry, Multidisciplinary
Victor V. Petrov, Irina O. Ignatieva, Maria G. Volkova, Irina A. Gulyaeva, Ilya V. Pankov, Ekaterina M. Bayan
Summary: Transparent Al-doped ZnO films were synthesized by solid-phase pyrolysis and characterized by XRD, SEM, and TEM. The films exhibit wurtzite structure and have a uniform distribution of nanoparticles. The introduction of 1% Al results in a narrowed band gap and improved response time to radiation.
Article
Chemistry, Physical
Giovanna Latronico, Saurabh Singh, Paolo Mele, Abdalla Darwish, Sergey Sarkisov, Sian Wei Pan, Yukihiro Kawamura, Chihiro Sekine, Takahiro Baba, Takao Mori, Tsunehiro Takeuchi, Ataru Ichinose, Simeon Wilson
Summary: The addition of 2% SnO2 significantly enhances the thermoelectric performance of AZO thin films on silica substrates, particularly in terms of power factor. Compared to typical AZO materials, the thermal conductivity is significantly reduced.
Article
Chemistry, Physical
Young-Hee Joo, Mi-Jin Jin, Sung Kyun Kim, Doo-Seung Um, Chang-Il Kim
Summary: In this study, the etching mechanism of Al-doped ZnO thin films in a BCl3/Ar-based plasma system was investigated. It was found that the etch rate was highest at a BCl3/Ar ratio of 25:75, and the surface properties of the thin films improved after etching. These findings may have potential applications in the development of high-performance optical and electronic devices.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Stefan Petrov, Dimitrina Petrova, Chau Nguyen Hong Minh, Vera Marinova, Blagovest Napoleonov, Yu-Pin Lan, Vladimira Videva, Blagoy Blagoev, Velichka Strijkova, Ken Yuh Hsu, Dimitre Dimitrov, Shiuan Huei Lin
Summary: This study demonstrates the feasibility of using transparent and conductive Aluminum-doped Zinc Oxide (AZO) thin films as electrodes and alignment layers in Liquid Crystal (LC) devices. The AZO thin films, grown by Atomic Layer Deposition (ALD), exhibit high transparency and excellent conductivity. The study also provides insights into the mechanism of LC molecule alignment on the surface of the AZO film, and confirms the uniform vertical orientation of the LC director.
Article
Physics, Multidisciplinary
Xinqiang Cai, Zhilin Xu, Shuai-Hua Ji, Na Li, Xi Chen
Summary: This study reports the successful growth of monolayers of MnI2, GdI3, and CrI2 through molecular beam epitaxy. The thin films of these materials are found to be insulators with different bandgaps. This paves the way for further research on magnetic properties at the 2D limit.
Article
Nanoscience & Nanotechnology
Riya Nag, Rama Kanta Layek, Abhijit Bera
Summary: Transparent, flexible, and chemically stable conducting electrodes are crucial for optoelectronic device fabrication. This study explores metal-semiconductor (MS) junctions utilizing two-dimensional (2D) MXene nanosheets and Al-doped ZnO nanoparticles. The heterojunctions were formed by layer-by-layer self-assembly on an indium tin oxide (ITO) substrate and characterized using scanning tunneling microscopy (STM) and spectroscopy. The results demonstrate the ability to manipulate the MS junction properties, such as rectification ratio and contact resistance, by functionalizing the 2D-metal MXene and doping the ZnO nanoparticles.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Physical
Dilawar Ali, M. Z. Butt, I Muneer, F. Bashir, M. Hanif, Taj M. Khan, Shahab Ahmed Abbasi
Summary: Highly c-axis oriented ZnO thin films with wurtzite structure were grown onto preheated glass using spray pyrolysis technique with varying Al/Zn ratios. The films exhibited good optical properties and antibacterial activity against Escherichia Coli bacteria, with enhanced efficacy on increasing Al/Zn ratio. These antimicrobial coatings have potential applications in surgical instruments, protective hospital apparels, medical implants, storage containers, textile, and food packs.
SURFACES AND INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
M. Isik, N. M. Gasanly
Summary: In this study, Al-doped ZnO nanostructured thin films were produced using AZO ink, and their structural characteristics were analyzed using XRD and SEM techniques. The results showed that the AZO thin films had a well-defined hexagonal crystal structure, and the size of the nanostructure particles varied between 20 and 30 nm. It was also found that the bandgap energy of the Al-doped ZnO nanostructured films changed with temperature, and this temperature-bandgap energy dependency was studied using transmission experiments and mathematical models.
Article
Materials Science, Ceramics
Hassan Guendouz, Abdelhamid Bouaine, Noureddine Brihi
Summary: Transparent amorphous Sn-Al co-doped ZnO thin films were prepared using a sol-gel spin-coating technique. The films exhibited a combination of two different amorphous phases, with the dominant phase showing high near ultraviolet transparency and ultrawide bandgap, while the minor phase had low transparency and bandgap. Control of the amorphous structure allowed for achieving desired properties such as near ultraviolet transparency and bandgap, with the lowest resistivity found at a specific Sn-Al concentration. The a-SAZO films with low resistivity have the potential to replace a-IGZO films in certain applications.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2021)
Article
Chemistry, Physical
Riccardo Magrin Maffei, Alessandro di Bona, Maria Sygletou, Francesco Bisio, Sergio D'Addato, Stefania Benedetti
Summary: In this study, we demonstrate that Al-doped ZnO (AZO) thin films grown epitaxially on SrTiO3 retain their optimal properties even at very small thicknesses. We investigate the film morphology, structure, crystallinity, electrical and optical properties. The results reveal that the epitaxial films exhibit high mobility due to ionized impurity scattering, while the polycrystalline films show deteriorated properties due to grain boundary scattering.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Ceramics
Koji Abe, Tasuku Kubota
Summary: Al-doped ZnO (AZO) films were prepared by sol-gel method using precursor solutions containing oxygen sources. Zinc vacancy acceptors were formed under oxygen-rich growth conditions. Glass substrates with a zinc layer were used to supply zinc to the AZO films during calcination annealing. The AZO films showed wurtzite ZnO crystal structure and high transparency. The electrical properties of the films were improved by using substrates with a zinc layer, achieving a low resistivity of 9.4 x 10(-4) Ocm.
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
(2023)
Article
Chemistry, Physical
Dung Van Hoang, Nam Hoang Vu, Nga Thi Do, Anh Tuan Thanh Pham, Truong Huu Nguyen, Jer-Lai Kuo, Thang Bach Phan, Vinh Cao Tran
Summary: This study distinguishes the roles of hydrogen in improving electron mobility and carrier concentration in ZnO and Al doped ZnO sputtered films. The experimental and theoretical results show that hydrogen located at oxygen vacancy sites is the main factor contributing to the simultaneous increase in mobility and carrier concentration. Introducing appropriate hydrogen content during sputtering not only relaxes the crystal structure, but also supports aluminum doping, resulting in increased carrier concentration and electron mobility in the film.
JOURNAL OF MATERIOMICS
(2022)
