多孔硅基热敏薄膜的制备与性能

对MEMS用具有绝热性能的多孔硅基底上沉积的热敏感薄膜进行了研究．首先用电化学方法制备多孔硅,分别在多孔硅基底和硅基底上通过溅射镀膜方法沉积氧化钒、Cu、Au热敏薄膜,测试多孔硅基底和硅基底上的氧化钒及金属薄膜电阻的热敏特性．结果表明,在多孔硅基底表面沉积的热敏薄膜具有与硅基表面热敏薄膜同样的热敏特性且表现出更高的灵敏度;此外,对沉积在不同制备条件得到的多孔硅上的氧化钒薄膜电阻热敏特性进行比较,发现随着孔隙率和厚度的增加,多孔硅的绝热性能提高,其上沉积的氧化钒薄膜电阻热敏特性增强．     

多孔硅表面氧化钒热敏电阻薄膜的阻温特性

用电化学腐蚀法制备了具有不同导热系数的多孔硅样品(孔隙率为80％±2、厚度为110μm时,导热系数可降低至0．20 W／m·K),并在其表面沉积了氧化钒热敏薄膜,研究了多孔硅样品的热绝缘性能对氧化钒热敏薄膜阻温特性的影响．结果表明:多孔硅良好的热绝缘性使在其表面制备的氧化钒热敏薄膜电阻的灵敏度远高于在硅基底上制备的热敏电阻的(多孔硅和硅片上的氧化钒薄膜电阻随功率变化斜率分别为120 kΩ／μW和2．1 kΩ／μW),且热敏电阻的灵敏度随着多孔硅孔隙率和厚度的增大而升高．     

氧化法热处理温度对氧化钒薄膜热敏特性的影响

采用直流磁控溅射法制备氧化钒薄膜,并采用不同的温度对其进行氧化法热处理,通过XRD、SEM、四探针薄膜电阻测试,分析了不同热处理温度对氧化钒薄膜的晶相特性与热敏特性的影响。实验分析证明热处理温度升高后(400℃)得到的薄膜热敏特性良好,其室温电阻为160KΩ·cm,室温电阻温度变化系数为-2.4%/℃,变温过程中(20~98℃)其平均值约-1.98%/℃,表明温度升高有利于改善薄膜热敏特性,在非制冷红外探测器应用方面具有发展潜力。     

氧化钒薄膜的厚度对薄膜电学特性的影响

利用直流反应磁控溅射法在表面覆盖有Si3N4薄膜的Si(100)基片上制备了不同厚度的氧化钒薄膜.用光谱式椭偏仪对薄膜的厚度进行了测试.采用四探针测试系统对制备的薄膜进行了方阻和方阻温度系数的分析,发现薄膜的厚度对薄膜的电学特性有很大的影响.实验结果表明氧化钒薄膜的厚度调整可作为调控氧化钒薄膜性能的一种重要工艺手段.     

氩流量对氧化钒薄膜直流磁控溅射制备的影响

在氧化钒薄膜的直流磁控溅射制备中,氩流量是影响沉膜工艺以及薄膜织构和性能的重要因素之一.从氧化钒薄膜制备角度出发,研究了纯氩环境以及氧流量恒定的氩氧混合环境中溅射电压和薄膜沉积速率随氩流量的变化.实验结果有助于对氧化钒薄膜制备工艺进行优化,为氩气流量的选择提供参考.     

氧化钒薄膜成分及价态的深度刻蚀分析

采用直流反应磁控溅射法制备了厚度为500nm的氧化钒薄膜.采用X射线光电子能谱仪对制得的氧化钒薄膜进行了深度刻蚀分析.结果表明,随薄膜刻蚀深度的增加,薄膜内的氧钒比及钒离子价态发生了递变,当薄膜刻蚀深度小于80nm时,这一递变趋势尤为明显.认为这与氧化钒薄膜中各价态钒氧化合物的稳定性和薄膜的制备工艺密切相关.     

晶粒尺寸对氧化钒薄膜电学与光学相变特性的影响

采用直流对靶磁控溅射方法制备氧化钒薄膜,通过改变热处理温度获得了具有不同晶粒尺寸的相变特性氧化钒薄膜,对氧化钒薄膜相变过程中电阻和红外光透射率随温度的突变性能进行研究.结果表明:经300℃和360℃热处理后,薄膜内二氧化钒原子分数达到40%,氧化钒薄膜具有绝缘体-金属相变特性,薄膜的晶粒尺寸分别为50nm和100nm;...     

氧化钒薄膜的制备技术及特性研究

采用直流反应磁控溅射法,通过精确控制反应溅射电压优化了氧化钒薄膜的制备工艺.对制备的氧化钒薄膜,利用四探针测试仪检测了薄膜的方阻和方阻温度系数,用X射线光电子能谱(XPS)仪和原子力显微镜(AFM)对薄膜的钒氧原子比和薄膜的微观形貌分别进行了分析和表征.实验结果表明,利用精确控制反应溅射电压法生长出的氧化钒薄膜的性能得到了进一步的提高.     

氧化钒薄膜的制备技术及特性研究

采用直流反应磁控溅射法，通过精确控制反应溅射电压优化了氧化钒薄膜的制备工艺。对制备的氧化钒薄膜，利用四探针测试仪检测了薄膜的方阻和方阻温度系数，用X射线光电子能谱（XPS）仪和原子力显微镜（AFM）对薄膜的钒氧原子比和薄膜的微观形貌分别进行了分析和表征。实验结果表明，利用精确控制反应溅射电压法生长出的氧化钒薄膜的性能得到了进一步的提高。     

用于微测辐射热计的氧化钒薄膜的光电性能研究

采用磁控溅射方法在p-Si(100)衬底上制备了VO2和择优取向的V6O13混合相成分的薄膜.利用X射线衍射(XRD)分析、原子力显微镜(AFM)、傅立叶红外光谱(FT-IR)分析及四探针测试方法,研究了薄膜的相成分和红外吸收特性,并测试分析了薄膜的电学热稳定性.研究结果表明,通过这种方法制备的氧化钒薄膜具有较低的电阻率和较高的电阻温度系数(TCR),并且具有良好的热稳定性,可以作为微测辐射热计的热敏材料.     

氧化钒薄膜制备与特性研究

用磁控反应溅射法制备出具有红外敏感特性的氧化钒薄膜,进行了薄膜光电特性的测试.通过AFM和XRD对薄膜的结构和特性进行分析研究,并给出了沉积参数对薄膜性能的影响.     

Work function of vanadium dioxide thin films across the metal-insulator transition and the role of surface nonstoichiometry

Vanadium dioxide (VO(2)) undergoes a sharp metal-insulator transition (MIT) in the vicinity of room temperature and there is great interest in exploiting this effect in novel electronic and photonic devices. We have measured the work function of vanadium dioxide thin films across the phase transition using variable temperature Kelvin force microscopy (KFM). The work function is estimated to be ～5.15 eV in the insulating phase and increases by ～0.15 eV across the MIT. We further show that the work function change upon the phase transition is highly sensitive to near-surface stoichiometry studied by X-ray photoelectron spectroscopy. This change in work function is distinct from bulk resistance-versus temperature trends commonly used to evaluate synthesis protocols for such vanadium oxide films and optimize stoichiometry. The results are pertinent to understanding fundamental electronic properties of vanadium oxide as well as charge injection phenomena in solid-state devices incorporating complex oxides containing multivalence cations.     

Nano-polycrystalline vanadium oxide thin films prepared by pulsed laser deposition

Nano-polycrystalline vanadium oxide thin films have been successfully produced by pulsed laser deposition on Si(100) substrates using a pure vanadium target in an oxygen atmosphere. The vanadium oxide thin film is amorphous when deposited at relatively low substrate temperature (500 degrees C) and enhancing substrate temperature (600-800 degrees C) appears to be efficient in crystallizing VOx thin films. Nano-polycrystalline V3O7 thin film has been achieved when deposited at oxygen pressure of 8 Pa and substrate temperature of 600 degrees C. Nano-polycrystalline VO2 thin films with a preferred (011) orientation have been obtained when deposited at oxygen pressure of 0.8 Pa and substrate temperatures of 600-800 degrees C. The vanadium oxide thin films deposited at high oxygen pressure (8 Pa) reveal a mix-valence of V5+ and V4+, while the VOx thin films deposited at low oxygen pressure (0.8 Pa) display a valence of V4+. The nano-polycrystalline vanadium oxide thin films prepared by pulsed laser deposition have smooth surface with high qualities of mean crystallite size ranging from 30 to 230 nm and Ra ranging from 1.5 to 22.2 nm. Relative low substrate temperature and oxygen pressure are benifit to aquire nano-polycrystalline VOx thin films with small grain size and low surface roughness.     

Electron back-scattered diffraction of crystallized vanadium dioxide thin films on amorphous silicon dioxide

Crystalline films and isolated particles of vanadium dioxide (VO₂) were obtained through solid phase crystallization of amorphous vanadium oxide thin films sputtered on silicon dioxide. Electron back-scattered diffraction (EBSD) was used to study the crystals obtained in the thin films, to differentiate them from different vanadium oxide stoichiometries that may have formed during the annealing process, and to study their phase and orientation. EBSD showed that the crystallization process yielded crystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated particles, and did not show evidence of other vanadium oxide stoichiometries present. Indexing of the crystals for the orientation study was performed using EBSD patterns for the tetragonal phase of vanadium dioxide, since it was observed that EBSD patterns for the monoclinic and tetragonal phases of vanadium dioxide are not distinguishable by computer automated indexing. Using the EBSD patterns for the tetragonal phase of vanadium dioxide, orientation maps showed that all VO₂ crystals that were measurable (approximately the thickness of the film) had a preferred orientation with the c-axis of the tetragonal phase parallel to the plane of the specimen.     

Tuning temperature-dependent microstructural properties of tungsten oxide thin films for acetone sensor

Journal of Materials Science: Materials in Electronics - In this paper, the physical properties of thermally evaporated tungsten oxide thin films and their performance towards acetone sensors are...     

Investigation of structural,optical, antibacterial,and dielectric properties of V-doped copper oxide thin films: Comparison with undoped copper oxide thin films

Vanadium doped Copper oxide (CO) thin films were prepared by the sol-gel dip-coating method. The properties of thin films were examined by X-Ray Diffractometer (XRD), UV–Visible-NIR spectrophotometry, and dielectric properties analyzer. The antibacterial and photocatalytic properties were also determined. XRD spectra revealed the dual-phase of copper oxide (cuprite and tenorite) for all percentages of V with no other impurity peak. Tauc's relation is used to probe the optical band gap which is reduced from 1.96 to 1.64 eV with an increase in vanadium doping percentage. The impurity band coalesces with the conduction band of copper oxide to decrease the band gap. Dielectric constant measurements reveal that the Ac conductivity of thin films increases with an increase in V doping percentage.     

双靶磁控溅射制备掺W氧化钒薄膜的研究

用双靶磁控溅射制备了掺钨氧化钒薄膜。Ｘ射线电子谱（ＸＰＳ）对所沉积的薄膜进行了分析,发现掺Ｗ氧化钒薄膜的相结构比较复杂。通过特征峰标定了这些相。用面积灵敏度因子方法得到Ｗ掺杂量的结果。原子力显微镜给出了薄膜的表面形貌。其表面形貌特征随沉积条件的不同有一定的变化。     

Investigation of physicochemical and tribological properties of transparent oxide semiconducting thin films based on Ti-V oxides

In this paper investigations of structural and optical properties of nanocrystalline Ti-V oxide thin films are described. The films were deposited onto Corning 7059 glass using a modified reactive magnetron sputtering method. Structural investigations of prepared Ti-V oxides with vanadium addition of 19 at. % revealed amorphous structure, while incorporation of 21 and 23 at. % of vanadium resulted in V₂O₅ formation with crystallites sizes of 12.7 and 32.4 nm, respectively. All prepared thin films belong to transparent oxide semiconductors due to their high transmission level of ca. 60–75 % in the visible light range, and resistivity in the range of 3.3·10²–1.4·10⁵ Ωcm. Additionally, wettability and hardness tests were performed in order to evaluate the usefulness of the films for functional coatings.     

氧化钒薄膜在玻璃基片上的生长研究

采用直流反应磁控溅射法, 在平整光滑的普通玻璃基片表面沉积了厚度分别为80nm、440nm和1μm的氧化钒薄膜. 采用原子力显微镜(AFM)、扫描电镜(SEM)和X射线衍射仪(XRD)对薄膜的表面形貌、结构和结晶化的分析表明, 厚度影响着薄膜的颗粒大小和结晶状态, 随着薄膜厚度的增加, 薄膜的颗粒增大, 晶化增强; 薄膜具有明显的垂直于衬底表面的“柱”状择优生长特征. 对薄膜的方阻和方阻随温度的变化进行了相关分析, 证实了厚度对氧化钒薄膜的电学性能存在明显的影响, 随着薄膜厚度的增加, 薄膜的方阻减小, 方阻温度系数升高, 薄膜的方阻随温度变化的回线滞宽逐渐增大, 薄膜的金属-半导体相变逐渐趋于明显.