Article
Chemistry, Physical
Hansung Kim, Gunwu Ju, Seung-Hwan Kim, Kiyoung Lee, Myoungho Jeong, Hyun Cheol Koo, Hyung-jun Kim
Summary: The study utilized interdiffusion between epitaxial Ge layers and GaAs substrates to control the doping concentration and type of the Ge layers, achieving extremely high n-type doping concentration in a Ge layer grown at low temperature. Subsequent annealing processes led to a decrease in doping concentration and an n- to p-type transition due to differences in diffusivity between As and Ga atoms.
SURFACES AND INTERFACES
(2021)
Article
Multidisciplinary Sciences
Yusaku Magari, Taiki Kataoka, Wenchang Yeh, Mamoru Furuta
Summary: Hydrogenated polycrystalline In2O3 thin-film transistors grown via low-temperature solid-phase crystallization process exhibit superior switching properties and field-effect mobility, showing potential for future transparent or flexible electronics applications.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Jiajia Lu, Liangfeng Li, Bo Zhou, Xue Ma, Hongxuan Yan
Summary: The study investigated ZnO-Bi2O3-MnO2-SiO2-TiO2 varistor ceramics with the addition of X2O3 (X = In, La, Ga) and found that doping Ga2O3 refines grain sizes, while doping In2O3 increases the nonlinear coefficient.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
Liang Liu, Brahim Mezari, Nikolay Kosinov, Emiel J. M. Hensen
Summary: In this study, a series of In2O3-Al2O3 samples were prepared using flame spray pyrolysis, and the promoting role of Al in In2O3 was investigated. It was found that Al doping can enhance the methanol yield by increasing oxygen vacancies for CO2 adsorption and methanol formation. Additionally, small Al2O3 domains formed on the In2O3 surface contribute to higher CO selectivity by blocking active sites for CO2 hydrogenation.
Article
Chemistry, Multidisciplinary
Haiyang Shan, Qing Jiao, Yeting Zhang, Baochen Ma, Pingping Dong, Tiefeng Xu
Summary: A novel sulfide-based sodium-ion electrolyte with optimized network structure and good physical properties was prepared in this study, showing superior ionic conductivity compared to traditional glass systems. Conductivity differences were attributed to microstructural changes in ion channels and crystal growth, with an optimal glass composition designed based on analytical results.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Engineering, Electrical & Electronic
Jose Menendez, Chi Xu, John Kouvetakis
Summary: A consistent methodology is proposed to extract carrier concentrations in n-type Ge from measurements of the infrared dielectric function and the Hall effect. The carrier concentration obtained from optical measurements is affected by the conductivity effective mass dependence on doping, while the carrier concentration obtained from Hall measurements requires knowledge of the Hall factor. Calculations of the Hall factor for n-Ge are presented and it is shown that determinations of the carrier concentration using the computed effective mass and Hall factor eliminate systematic discrepancies between the two types of measurement.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Engineering, Electrical & Electronic
Francesco Sgarbossa
Summary: With the growing interest in nanoelectronics and photonics, there is a need to develop new doping methods for new germanium challenges. The monolayer doping technique shows promise in nanostructure doping due to its ability to perform conformal doping on nanostructured materials, absence of lattice damage, precise dopant control, and reduction of stochastic doping effects.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Chemistry, Multidisciplinary
Shasha Li, Xinan Zhang, Penglin Zhang, Guoxiang Song, Li Yuan
Summary: This study explores the use of a semiconductor heterojunction channel layer to improve metal oxide thin-film transistor (TFT) performance. The researchers successfully fabricated In2O3/In2O3:Gd heterojunction TFTs using a solution process, which exhibited excellent electrical properties. By adjusting the Gd dopant concentration, they achieved a TFT with higher saturation mobility, near-zero threshold voltage, small off-state current, large on/off current ratio, small subthreshold swing, and appropriate positive bias stability. Furthermore, long-term air stability and optimal switching properties were observed in the aging test.
Article
Chemistry, Physical
Jianqiao Hao, Shuyang Qin, Longge Yan, Xinfang Zhang
Summary: Electropulsing can break through the limitations of thermal homogenization process, reducing dissolution temperature and increasing atomic diffusion rate, thereby shortening processing time, preventing grain growth, and improving workability.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Multidisciplinary
Stefano Cecchi, Inaki Lopez Garcia, Antonio M. Mio, Eugenio Zallo, Omar Abou El Kheir, Raffaella Calarco, Marco Bernasconi, Giuseppe Nicotra, Stefania M. S. Privitera
Summary: This study investigates the composition of Ge-rich Ge2Sb2Te5 alloy and finds that it is less prone to decompose and segregate germanium.
Article
Materials Science, Ceramics
Shrishti Uniyal, Neetu Yadav, Sitharaman Uma, Rajamani Nagarajan
Summary: The study successfully prepared Hf/Zr substituted In2O3 using a co-complexation method, demonstrating potential for a transparent conducting oxide. Changes in material structure and optical properties were confirmed, providing new insights for future research on transparent conducting oxides.
CERAMICS INTERNATIONAL
(2022)
Article
Chemistry, Inorganic & Nuclear
Xiaoqing Liang, Xiaojie Li, Nan Gao, Xue Wu, Zhi Zhao, Ruili Shi, Yan Su, Jijun Zhao
Summary: In this study, a comprehensive genetic algorithm combined with density functional theory (CGA-DFT) was used to investigate the structural and electronic properties of monoanionic Ru2Gen- (n = 3-20) clusters. The results reveal that the geometric growth patterns of the ground state Ru2Gen- clusters vary with cluster size, and the presence of an extra electron affects the geometric structures. Based on the obtained ground state structures, it is found that Ru2Ge10-, Ru2Ge12-, and Ru2Ge14- clusters exhibit relatively higher structural and chemical stability, with Ru2Ge14- showing the most prominent stability.
INORGANICA CHIMICA ACTA
(2022)
Article
Materials Science, Multidisciplinary
Bailing An, Rongmei Niu, Yan Xin, William L. Starch, Zhaolong Xiang, Yifeng Su, Robert E. Goddard, Jun Lu, Theo M. Siegrist, Engang Wang, Ke Han
Summary: The addition of Sc in Cu-6 wt%Ag alloy suppresses discontinuous precipitation and enhances continuous precipitation, resulting in increased strength and slightly decreased electrical conductivity. Sc inhibits the nucleation of discontinuous precipitates and forms a thin intermetallic compound layer. After deformation, both discontinuous and continuous precipitates form Ag fibers, and the combination of deformation strain and doping leads to increased fiber density and decreased diameter, resulting in increased strength.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Ceramics
Qingquan Hou, Bin Yang, Chao Ma, Zhiyong Zhou, Ruihong Liang, Hao Li, Xianlin Dong
Summary: This study investigates the effect of W6+ doping on the crystal structure, microscopic morphology, and electrical properties of calcium bismuth niobate ceramics. It was found that appropriate W6+ doping can enhance the piezoelectric and thermal depoling properties of the material, providing a feasible approach to improve its potential applications in high temperature piezoelectric vibration sensors.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
M. H. Ghozza, I. S. Yahia
Summary: The nanocrystalline gadolinium-doped cadmium manganite with the general formula GdxCd1-xMnO3 was prepared and characterized, showing potential applications in oxygen sensor electrodes and resistive switching equipment due to its structural, electrical, and magnetic properties.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Chemistry, Physical
Mao-Hua Zhang, Niloofar Hadaeghi, Sonja Egert, Hui Ding, Hongbin Zhang, Pedro B. Groszewicz, Gerd Buntkowsky, Andreas Klein, Jurij Koruza
Summary: In this study, a general approach was demonstrated to promote the reversibility of the unique electric-field-induced phase transition in antiferroelectric materials by modifying the material's local structure. A new composition based on NaNbO3, (1- x)NaNbO3-xSrSnO(3), was designed using first-principles calculations and experimental characterization. The results showed that the addition of SrSnO3 can enhance the stability of the antiferroelectric order and increase the energy storage density of the modified compositions.
CHEMISTRY OF MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Katharina N. S. Schuldt, Hui Ding, Jean-Christophe Jaud, Jurij Koruza, Andreas Klein
Summary: The study on Schottky barrier formation between polycrystalline acceptor-doped BaTiO3 and high work function RuO2 using photoelectron spectroscopy revealed that the barrier height for electrons is approximately 1.4 eV, independent of doping level and oxygen vacancy concentration of the substrates. The high permittivity of BaTiO3 results in wider space-charge regions, making SCRs more important for electronic and ionic conductivities in BaTiO3 compared to materials with lower permittivity. A Ba-rich phase at the surface of reduced acceptor-doped BaTiO3 is also identified, explained by the formation of Ti vacancies in the 2D electron gas region at the surface.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
Philipp Wendel, Dominik Dietz, Jonas Deuermeier, Andreas Klein
Summary: ZnO/RuO2 Schottky diodes prepared by magnetron sputtering exhibit reversible hysteresis behavior in their current-voltage characteristics, with the Schottky barrier height varying between 0.9 and 1.3 eV during voltage cycling. This variation is attributed to trapping and de-trapping of electrons in oxygen vacancies.
Article
Chemistry, Physical
Raphael Poulain, Jochen Rohrer, Yannick Hermans, Christian Dietz, Joachim Brotz, Joris Proost, Marian Chatenet, Andreas Klein
Summary: The interaction between water and oriented NiO films was studied using a combination of photoelectron spectroscopy, in situ sample preparation, and electrochemical measurements. The exposure to room temperature water induced a more positive surface charge on the (110)- and (111)-oriented films compared to NiO(100), which was attributed to dissociative adsorption of water and removal of oxygen. This explains the role of water as an electron donor on oxide surfaces.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Hans F. Wardenga, Katharina N. S. Schuldt, Stephan Waldow, Roger A. De Souza, Andreas Klein
Summary: The study investigated the influence of different doping methods, concentrations, and surface orientations on the surface Fermi level positions, ionisation potentials, and work functions of CeO2. It was found that the ionisation potentials are significantly affected by doping and oxygen activity, while the work functions are largely unaffected. In terms of oxygen surface exchange coefficients, similar magnitudes were observed under different conditions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Elaheh Ghorbani, Lorenzo Villa, Paul Erhart, Andreas Klein, Karsten Albe
Summary: This study presents a systematic assessment of the behavior of self-trapped electrons in PbTiO3, a prototypical ferroelectric material with various technological applications. The study aimed to identify the parameters used in density functional theory (DFT) that accurately predict the properties of self-trapped electrons. It was found that the choice of pseudopotential and lattice parameters significantly influenced the magnitude of the trapping energy. A comparison of two different functionals showed the DFT-PU result to be close to the HSE06 result. The study also provided configuration coordinate diagrams for the polaron-associated absorption and luminescence peaks in PbTiO3.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Nicole Bein, Brigita Kmet, Tadej Rojac, Andreja Bencan Golob, Barbara Malic, Julian Moxter, Thorsten Schneider, Lovro Fulanovic, Maryam Azadeh, Till Froemling, Sonja Egert, Hongguang Wang, Peter van Aken, Jutta Schwarzkopf, Andreas Klein
Summary: The valence band maximum energy of NaNbO3 is determined and found comparable to SrTiO3 and BaTiO3, while the conduction band minimum is yet to be determined. In addition, Sr- and Ca-doped NaNbO3 ceramics exhibit low electrical conductivity.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Julia E. Medvedeva, Bishal Bhattarai, Ivan A. Zhuravlev, Federico Motti, Piero Torelli, Anita Guarino, Andreas Klein, Emiliano Di Gennaro, Fabio Miletto Granozio
Summary: Understanding the short-range structure of amorphous materials is crucial for predicting their macroscopic properties. This study investigates the contradictory experimental findings regarding the oxygen environment of titanium in amorphous strontium titanate and reveals that the discrepancy is caused by differences in the material's density. The study also analyzes the density-dependent structural characteristics and electronic properties of amorphous strontium titanate, providing insights into the structure-property relationship.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Issei Suzuki, Binxiang Huang, Sakiko Kawanishi, Takahisa Omata, Andreas Klein
Summary: This study demonstrates that the Fermi energy of SnS at the interface can be shifted through the entire band gap, indicating the absence of Fermi-level pinning. The mechanisms behind the existence or lack of Fermi-level pinning at SnS interfaces were discussed, and suggestions were offered to achieve higher photovoltages by avoiding Fermi-level pinning in SnS solar cells.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Applied
Yunwei Sheng, Mathieu Mirjolet, Mario Villa, Jaume Gazquez, Jose Santiso, Andreas Klein, Jordi Fraxedas, Josep Fontcuberta
Summary: Epitaxial LaFeO3-based photocells with different thicknesses were grown on LSAT single-crystal substrates, using LSMO and Pt/BLSO electrodes, to determine their photoresponse. The short-circuit photocurrent initially increases and then decreases with LFO thickness, and is larger or smaller with Pt or BLSO electrodes. The open-circuit voltage shows the opposite trend, being smaller or larger with Pt and BLSO, respectively, consistent with the electronic band alignments and rectifying character of the dark current-voltage data. The complex microstructure and grain boundaries of the films play a significant role in the observed responsivity, which is larger than in similar LFO-based structures.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Physical
Shanmugapriya Periyannan, Laura Manceriu, Andreas Klein, Wolfram Jaegermann, Catherine Henrist, Rudi Cloots
Summary: In this study, a surface cleaning procedure involving vacuum annealing under oxygen was employed to clean the ZNR scaffold film's surface before NiO deposition for heterostructure formation. The properties of the scaffold were studied and correlated to the NiO/ZNR interface and photo-response properties. The optimized NiO/ZNR showed improved photo-response and photodegradation efficiency compared to the ZNR scaffold.
Article
Chemistry, Multidisciplinary
Binxiang Huang, Paul Erhart, Tongqing Yang, Andreas Klein
Summary: Interface stability is crucial for the reliable performance of electronic and electrochemical devices. In this study, an operando analysis approach using photoelectron spectroscopy in a solid oxide electrochemical cell was introduced to investigate interfaces. The experiment provided chemical and electronic information, revealing the importance of both chemical and electrostatic boundary conditions for interface stability. The approach was demonstrated using (anti-)ferroelectric (Pb,La)(Zr,Sn,Ti)O-3 dielectrics.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Issei Suzuki, Zexin Lin, Taichi Nogami, Sakiko Kawanishi, Binxiang Huang, Andreas Klein, Takahisa Omata
Summary: Recently, it has been reported that there is a large band bending at the interface between n-type single crystalline SnS and MoO3, which has a high work function. In this study, we applied this interface to solar cells for the first time and evaluated its photovoltaic properties. The highest achieved open-circuit voltage (V-OC) was 437 mV, which is lower than the expected value but the highest recorded for SnS solar cells. The highest power conversion efficiency (PCE) was 4.4%. Based on device parameter analysis, we propose methods for improving the device performance, including V-OC, short-circuit current, and PCE. The study also estimated the carrier-collection length of n-type SnS single crystals to be around 200 nm using external quantum efficiency measurements. This study demonstrates that the V-OC of SnS solar cells can be improved by fabricating a junction with MoO3 thin films.
Article
Materials Science, Ceramics
Andreas Klein, Karsten Albe, Nicole Bein, Oliver Clemens, Kim Alexander Creutz, Paul Erhart, Markus Frericks, Elaheh Ghorbani, Jan Philipp Hofmann, Binxiang Huang, Bernhard Kaiser, Ute Kolb, Jurij Koruza, Christian Kuebel, Katharina N. S. Lohaus, Juergen Roedel, Jochen Rohrer, Wolfgang Rheinheimer, Roger A. Souza, Verena Streibel, Anke Weidenkaff, Marc Widenmeyer, Bai-Xiang Xu, Hongbin Zhang
Summary: Chemical substitution is a primary strategy for tailoring material properties, with isovalent and heterovalent substitution being the two types. By controlling the different compensation mechanisms, it is possible to predict and adjust material properties. The Fermi energy can be used as a common descriptor for these mechanisms.
JOURNAL OF ELECTROCERAMICS
(2023)
Article
Engineering, Electrical & Electronic
Raphael Poulain, Gunnar Lumbeeck, Jonas Hunka, Joris Proost, Henri Savolainen, Hosni Idrissi, Dominique Schryvers, Nicolas Gauquelin, Andreas Klein
Summary: Although there are contradictory results on the properties of nickel oxide (NiO) in the literature, this comprehensive study provides valuable insights into the conductivity, surface properties, and charge defects compensation mechanism of NiO materials. The experiments reveal that the surface and bulk properties of NiO are strongly influenced by the deposition temperature, leading to variations in the Fermi level pinning, work function, and grain boundaries. This study contributes to a better understanding of the electrical conductivity and charge compensation mechanism of NiO thin films.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
