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Thermal annealing induced evolution of AgIn5Se8 phase from Ag/In2Se3 bilayer thin film
摘要： In the present report, we have investigated the AgIn5Se8 phase formation upon annealing the Ag/In2Se3 bilayer film prepared by the thermal evaporation technique. The optical, morphology as well as structural parameters was tuned with different annealing temperature. The prominent crystalline phase developed at 2500C annealing where as there is no signal of this phase in the as-prepared film (amorphous). The analysis using XRD study showed the amorphous to crystalline phase transformation with annealing. The indirect as well as the direct band gap is found to be increased with annealing (up to 1500C) and then decreased due to the growing up new phase as explained by phase transformation and decrease in density of localized states. The formation of dangling bonds at the surface near the crystallite sites during crystallization process reduces the band gap. The Tauc parameter change shows the degree of chemical disorderness in the films. The transmitivity, absorption coefficient, oscillator energy, refractive index, dispersion energy and extinction coefficient are found to be changed accordingly with annealing condition.The micro structural study done by Scanning Electron Microscopyshows the formation of crystallites upon annealing. The Raman study of these films supports the formation of new phase.
关键词： bandgap,Thin films,annealing,optical properties,chalcopyrite,structural properties
更新于2025-09-10 09:29:36
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Evolutions on surface chemistry, microstructure, morphology and electrical characteristics of SnO2/p-Si heterojuction under various annealing parameters
摘要： The influences of annealing temperature and ambient on surface chemistry, microstructure, morphology and electrical characteristics of Tin Oxide (SnO2)/Si heterojuctions are systematically identified. Metallic and oxygen deficient SnO2-x bonds have been consistently treated to stoichiometric SnO2 with annealing temperatures up to 600 0C in nitrogen environment. It has been observed that further increase in the annealing temperature causes the formation of the silicate layer. Presence of hydrogen in forming gas environment causes formation of the oxygen deficient SnO2-x, while the presence of the oxygen contributes to the formation of the stoichiometric SnO2 layer in oxygen annealing ambient. Parasitic phases significantly affect the crystalline structure of the films. Surface roughness of the samples decreases up to 1.02 nm which is strongly correlated with stress and strain on the film. On the other hand, oxidations of the dangling bonds and/or hydrogen diffusion cause variations in the total dipole moments which significantly change the capacitance. Depending on the annealing parameters, effective charge densities and interface trap densities decrease to 1011 cm-2, while the ideality factor and barrier potential are improved to 1.43 and 0.59 eV, respectively. Owing to the crystallization of the SnO2 layer, leakage current increase at low temperature annealing. However, passivation of the dangling bonds becomes more effective than phase crystallization at higher temperatures on the leakage characteristics. The current study shows that any changes in the surface chemistry directly affect the device performance.
关键词： Tin Oxide,XPS,Oxide Films.,Heterojuction,Surface Chemistry,Annealing
更新于2025-09-10 09:29:36
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Atomic-layer-deposited (ALD) Al2O3 passivation dependent interface chemistry, band alignment and electrical properties of HfYO/Si gate stacks
摘要： In this work, the effects of atomic-layer-deposited (ALD) Al2O3 passivation layers with different thicknesses on the interface chemistry and electrical properties of sputtering-derived HfYO gate dielectrics on Si substrates have been investigated. The results of electrical measurements and X-ray photoelectron sepectroscopy (XPS) showed that 1-nm-thick Al2O3 passivation layer is optimized to obtain excellent interfacial properties for HfYO/Si gate stack. Then, the metal-oxide-semiconductor capacitors with HfYO/1-nm Al2O3/Si/Al gate stack were fabricated and annealed at different temperatures in forming gas (95% N2+5% H2). Capacitance-voltage (C-V) and current density-voltage (J-V) characteristics showed that the 250oC-annealed HYO high-k gate dielectric thin film demonstrated the lowest border trapped oxide charge density (-3.3 × 1010 cm-2), smallest gate-leakage current (2.45 × 10-6 A/cm2 at 2 V) compared with other samples. Moreover, the annealing temperature dependent leakage current conduction mechanism for Al/HfYO/Al2O3/Si/Al MOS capacitor has been investigated systematically. Detailed electrical measurements reveal that Poole-Frenkle emission is the main dominant emission in the region of low and medium electric fields while direct tunneling is dominant conduction mechanism at high electric fields.
关键词： Al2O3 passivation layer,Electrical properties,Annealing,Co-sputtering HYO films,Conduction mechanism
更新于2025-09-10 09:29:36
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Broadband UV-assisted thermal annealing of low- <i>k</i> silicon carbonitride films using a C-rich silazane precursor
摘要： Low-k dielectric silicon carbonitride (SiCxNy) films are deposited by plasma-enhanced chemical vapor deposition using a carbon-rich silazane precursor, N-methyl-aza-2,2,4-trimethylsilacyclopentane (SiC7NH17), at 100 °C. The post-treatments of SiCxNy films are carried out by thermal annealing and a broadband UV-assisted thermal annealing (UV-annealing) at 400 °C for 5 min. Compared to the thermal annealing treatment, UV-annealing can improve both dielectric and mechanical properties of low-k SiCxNy films. Under thermal annealing, SiCxNy films show great thermal stability, but little structural change. In contrast, upon UV-annealing, most of the Si–H and N–H bonds are broken up, which induces more Si–N cross-linking and converts Si–C matrix into Si–N matrix. The ethylene bridges in Si–(CH2)2–Si also remain intact, but the unbridged hydrocarbons in Si–(CH2)2–N and Si–CH2–CH3 bonds decompose completely during the UV-annealing process. These account for the reduced dielectric constant to k = 3.2 from 3.6 and a 21% enhancement of Young’s modulus to 7.4 GPa in the SiCxNy films after UV-annealing. Broadband UV-annealing shows promise as a post-treatment method for enhancing the properties of low-k dielectric barrier, SiCxNy films.
关键词： low-k dielectric,silicon carbonitride,UV-assisted thermal annealing,plasma-enhanced chemical vapor deposition,mechanical properties
更新于2025-09-10 09:29:36
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Raising the Operating Temperature of (Ga,Mn)As/GaAs Spin Light Emitting Diodes by Applying Post-Growth Treatment
摘要： Spin light emitting diodes (spin-LEDs) containing (Ga,Mn)As ferromagnetic layers are fabricated based on InGaAs/GaAs heterostructures and studied. We achieve increases in the operating temperatures of our spin-LEDs by subjecting the surface of the structures, prior to depositing an ohmic metal contact, to pulsed laser annealing. The fabricated devices produce circularly polarized electroluminescence when placed in an external magnetic field. The temperatures at which circularly polarized electroluminescence is still observed is raised from 30 K for unprocessed structure to 110 K for laser-annealed structures. The observed effect is linked to an increase in the Curie temperature of the (Ga,Mn)As layer as a result of laser impact.
关键词： ferromagnetic layers,circularly polarized electroluminescence,Curie temperature,Mn)As,pulsed laser annealing,Spin light emitting diodes,(Ga
更新于2025-09-10 09:29:36
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Enhancement of photoluminescence efficiency in GeSe ultrathin slab by thermal treatment and annealing: experiment and first-principles molecular dynamics simulations
摘要： The effect of thermal treatment and annealing under different temperatures from 100 °C to 250 °C on the photoluminescence spectroscopy of the GeSe ultrathin slab is reported. After the thermal treatment and annealing under 200 °C, we found that the photoluminescence intensity of A exciton and B exciton in GeSe ultrathin slab is increased to twice as much as that in untreated case, while is increased by ~84% in the photoluminescence intensity of C exciton. Combined by our experimental work and theoretical simulations, our study confirms the significant role of thermal treatments and annealing in reducing surface roughness and removing the Se vacancy to form more compact and smoother regions in GeSe ultrathin slab. Our findings imply that the improved quality of GeSe surface after thermal treatments is an important factor for the photoluminescence enhancement.
关键词： annealing,ultrathin slab,first-principles molecular dynamics,GeSe,photoluminescence,thermal treatment
更新于2025-09-10 09:29:36
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Chemical Vapor Deposited Vanadium Pentoxide Nanosheets with Highly Stable and Low Switching Voltages for Effective Selector Devices
摘要： Recently, attempts to overcome the physical limits of memory devices have led to the development of promising materials and architectures for next-generation memory technology. The selector device is one of the essential ingredients of high-density stacked memory systems. However, complicated constituent deposition conditions and thermal degradation are problematic, even with effective selector device materials. Herein, we demonstrate the highly stable and low threshold voltages of vanadium pentoxide (V2O5) nanosheets synthesized by facile chemical vapor deposition, which have not been previously reported on the threshold switching properties. The electrons occupying trap sites in poly-crystalline V2O5 nanosheet contribute to the perfectly symmetric threshold switching feature at the bias polarity and low threshold voltages in V2O5, confirmed by high-resolution transmission electron microscopy measurements. Furthermore, we find an additional PdO interlayer in V2O5 nanodevices connected with a Pd/Au electrode after thermal annealing treatment. The PdO interlayer decreases the threshold voltages, and the Ion/Ioff ratio increases because of the increased trap density of V2O5. These studies provide insight into V2O5 switching characteristics, which can support low power consumption in non-volatile memory devices.
关键词： nanosheets,selector devices,vanadium pentoxide,threshold switching,thermal annealing treatment
更新于2025-09-10 09:29:36
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Study of the oxidation at the Al <sub/>2</sub> O <sub/>3</sub> /GaSb interface after NH <sub/>4</sub> OH and HCl/(NH <sub/>4</sub> ) <sub/>2</sub> S passivations and O <sub/>2</sub> plasma post atomic layer deposition process
摘要： In this work, the Al2O3/GaSb interface has been studied by x-ray photoelectron spectroscopy in order to improve interfacial and electrical properties of metal–oxide–semiconductor structures based on GaSb. First, different passivations using NH4OH or (NH4)2S were studied with a dilution of 4% and 5%, respectively, in order to reduce native oxides on the GaSb surface. Then, we considered the oxidation of the Al2O3 and GaSb surface after treatments with an oxygen (O2) plasma post atomic layer deposition (ALD) process and with post deposition annealing at different temperatures. We found that (NH4)2S passivation leads to a lower quantity of native oxides on the GaSb surface and that the O2 plasma post ALD process enables the formation of an oxygen-rich layer within the Al2O3 at the interface reducing the GaSb surface oxidation after post deposition annealing of the oxide.
关键词： x-ray photoelectron spectroscopy,(NH4)2S,post deposition annealing,Al2O3/GaSb interface,NH4OH,atomic layer deposition,O2 plasma
更新于2025-09-10 09:29:36
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Micro-nano scale imaging and the effect of annealing on the perpendicular structure of electrical-induced VO2 phase transition
摘要： It was research hotspot that how to lower the threshold switching voltage (Vth), especially for the perpendicular structure of electrical-induced VO2 insulator-metal phase transition (MIT). This structure can reduce the Vth to the orders of 10-1 V. In micro-nano scale, combined with results of resistance change versus temperature, X-ray photoelectron spectroscopy measurements and conductive atomic force microscope, we had confirmed that V3+ was an important factor for electrical-induced VO2 thin MIT. On the one hand, joule heating produced by conductive V3+ region induced the surrounding VO2 region phase transition. On the other hand, with the annealing time increased from 0 min to 2 min at 470℃ in H2/N2 mixture gases, V3+ contents increased, thin film surface conductive areas increased, thin film resistance decreased, and finally resulted in threshold switching voltage decreased. Our experimental results were consistent with theory analysis. However, when the annealing time was too long (≥3 min), VO2 thin film threshold switching behavior disappeared, and current was linearly increased with voltage.
关键词： Perpendicular structure of electrical-induced VO2 MIT,Annealing process,Micro-nano scale current mapping,perpendicular VO2 thin film structure,threshold switching voltage
更新于2025-09-09 09:28:46
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Annealing effects on the properties of tin thin films
摘要： The structure, absorption coefficient and electrical resistivity studies on TiN thin films are presented. The film of thickness 240 nm was grown on Si (100) substrate by DC reactive sputtering at an average deposition rate of ～8 nm/min. After deposition the samples were annealed for 1 h at 600 °C and 2 h at 700 °C in nitrogen ambient and vacuum furnace, respectively. Structural characterizations were performed by Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optical properties were investigated by spectroscopic ellipsometry while a four point probe was used for electrical characterization. It was found that the post-deposition annealing of the films did not cause any variation in stoichiometry, but strongly affects the structural parameters such as lattice constant, micro-strain and grain size. The observed increase in the grain size after annealing leads to significantly lower value of the coefficient of absorption. These changes could be directly correlated with variation of electrical properties of TiN thin films.
关键词： RBS,annealing,sputtering,thin film,XRD,titanium nitride,TEM
更新于2025-09-09 09:28:46