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The current-voltage characteristics of the ferroelectric p-YMnO3 thin film/bulk p-Si heterojunction over a broad measurement temperature range
摘要： The reverse and forward bias I-V characteristics of the Al/p-YMO/p-Si/Al heterojunction were measured at room temperature (RT) and over temperature range, from 50 to 320 K, and the I-V curves showed Schottky diode-like characteristics. The ideality factor and barrier height values were calculated as 0.81 and 2.62 from the forward bias I-V curve at room temperature (300 K), respectively. The YMO powder was prepared via solid state reaction technique. YMO thin films were grown on front surface of p-Si substrate by radio frequency (rf) magnetron sputtering using a polycrystalline YMO single target. The YMO thin film thickness on Si substrate was measured as ~70 nm via Dektak XT surface profilometer. The XRD, SEM, UV-Vis and XPS measurements of the YMO thin film were also performed. The bandgap energy of YMnO3 thin films was determined as 2.10 eV by UV-vis. The temperature-dependent reverse and forward bias I-V curves were evaluated in terms of thermionic emission (TE), Schottky emission, Fowler-Nordheim (F-N) tunneling and space charge-limited current (SCLC) current theories. Furthermore, it has been seen that the forward bias conduction in the junction at each temperature obeys F-N tunneling because of the linearity in the ln (I/V2) versus V-1 curves.
关键词： Polycrystalline,Heterojunction,Ferroelectric,Al/p-YMO/p-Si/Al,Schottky barrier,YMnO3,Temperature dependent current characteristics
更新于2025-09-23 15:23:52
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Oxygen vacancies in the bulk and at neutral domain walls in hexagonal
摘要： We use density functional calculations to investigate the accommodation and migration of oxygen vacancies in bulk hexagonal YMnO3, and to study interactions between neutral ferroelectric domain walls and oxygen vacancies. Our calculations show that oxygen vacancies in bulk YMnO3 are more stable in the Mn-O layers than in the Y-O layers. Migration barriers of the planar oxygen vacancies are high compared to oxygen vacancies in perovskites, and to previously reported values for oxygen interstitials in h-YMnO3. The calculated polarization decreases linearly with vacancy concentration, while the out-of-plane lattice parameter expands in agreement with previous experiments. In contrast to ferroelectric perovskites, oxygen vacancies are found to be more stable in bulk than at domain walls. The tendency of oxygen vacancies to segregate away from neutral domain walls is explained by unfavorable Y-O bond lengths caused by the local strain field at the domain walls.
关键词： oxygen vacancies,ferroelectric domain walls,hexagonal YMnO3,density functional calculations,migration barriers
更新于2025-09-11 14:15:04
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Effect of Os doping on electrical properties of YMnO3 multiferroic perovskite-oxide compounds
摘要： In this study, YMnO3 (YMO) and osmium (Os) doped YMO (YMn1-xOsxO3) (x = 0.01, 0.05, 0.10) compounds were synthesized via conventional solid-state reaction and their frequency and temperature depended electrical properties were investigated by wide range dielectric/impedance spectrometer. Structural and chemical analysis of YMO and Os doped YMO powders were carried out using via scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS). Impedance measurement results revealed that only grain boundary relaxation peak observed for YMO and 1 mol% Os doped YMO whereas both grain boundary and grain relaxation peaks observed for 5 mol% and 10 mol% Os doped samples. It has been seen that resistivity of the YMO can be decreased via Os doping and we observed that 10 mol% Os doped sample has the lowest resistivity among the other samples. The activation energies of YMO and Os doped YMO compounds were calculated. The results showed that the activation energy values of studied compounds gradually decreased via increasing Os doping ratio. Moreover, it has been demonstrated that the grain boundaries have higher energies that the grains.
关键词： Multiferroic,YMnO3,Perovskite-oxide,Electrical properties,Os doping
更新于2025-09-10 09:29:36
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Structural, Morphological and Photocatalytic Activity of YMnO <sub/>3</sub> Nanorods
摘要： In this work rod-like YMnO3 were successfully prepared by hydrothermal method. The crystal structure and morphology of prepared samples were characterized by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The structural information was confirmed from Raman spectrum and the functional group of the sample was studied from FT-IR spectrum. X-ray photoelectron spectroscopy studies confirm the formation and oxidation states of YMnO3. The optical properties of the prepared samples were investigated using UV-vis spectroscopy. The photocatalytic activity of YMnO3 nanorods was evaluated by degradation of methyl orange (MO) under both ultraviolet and visible-light irradiation. The result shows that the YMnO3 nanorods exhibit maximum photocatalytic activity in the degradation of MO.
关键词： YMnO3 Nanorods,Hydrothermal,Methyl Orange,Photocatalytic
更新于2025-09-04 15:30:14