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1.
The present work deals with the mixing of iron and silicon by swift heavy ions in high-energy range. The thin film was deposited
on a n-Si (111) substrate at 10−6 torr and at room temperature. Irradiations were undertaken at room temperature using 120 MeV Au+9 ions at the Fe/Si interface to investigate ion beam mixing at various doses: 5 × 1012 and 5 × 1013 ions/cm2. Formation of different phases of iron silicide has been investigated by X-ray diffraction (XRD) technique, which shows enhancement
of intermixing and silicide formation as a result of irradiation. I-V measurements for both pristine and irradiated samples have been carried out at room temperature, series resistance and barrier
heights for both as deposited and irradiated samples were extracted. The barrier height was found to vary from 0·73–0·54 eV.
The series resistance varied from 102·04–38·61 kΩ. 相似文献
2.
This paper reports the effect of swift (80 MeV) oxygen (O+6) ion irradiation on the optical properties of CdTe thin films grown by conventional thermal evaporation on glass substrates. The films are found to be slightly Te-rich in composition and irradiation results no change in the elemental composition. The optical constants such as refractive index (n), absorption coefficient (α) and the optical band gap energy show significant variation in their values with increase in ion fluence. Upon irradiation the band gap energy decreased from a value of 1.53 eV to 1.46 eV whereas the refractive index (n) increased from 2.38 to 3.12 at λ = 850 nm. The photoluminescence spectrum shows high density of native defects whose density strongly depends on the ion fluence. Both analyses indicate considerable defect production after swift ion beam irradiation. 相似文献
3.
The present work deals with the mixing of metal and silicon by swift heavy ions in high-energy range. Threshold value for
the defect creation in metal Fe calculated was found to be ∼ 40 keV/nm. A thin film of Fe (10 nm) was deposited on Si (100)
at a pressure of 4 × 10−8 Torr and was irradiated with 95 MeV Au ions. Irradiation was done at RT, to a dose of 1013 ions/cm2 and 1 pna current. The electronic energy loss was found to be 29.23 keV/nm for 95 MeV Au ions in Fe using TRIM calculation.
Compositional analysis of samples was done by Rutherford backscattering spectroscopy. Reflectivity studies were carried out
on the pre-annealed and post-annealed samples to study irradiation effects. Grazing incidence X-ray diffraction was done to
study the interface. It was observed that ion beam mixing reactions at RT lead to mixing as a result of high electronic excitations. 相似文献
4.
Garima Agarwal Ankur Jain Shivani Agarwal D. Kabiraj I. P. Jain 《Bulletin of Materials Science》2006,29(2):187-191
Synthesis of swift heavy ion induced metal silicide is a new advancement in materials science research. We have investigated
the mixing at Co/Si interface by swift heavy ion beam induced irradiation in the electronic stopping power regime. Irradiations
were undertaken at room temperature using 120 MeV Au ions at the Co/Si interface for investigation of ion beam mixing at various
doses: 8 × 1012, 5 × 1013 and 1 × 1014 cm−2. Formation of different phases of cobalt silicide is identified by the grazing incidence X-ray diffraction (GIXRD) technique,
which shows enhancement of intermixing and silicide formation as a result of irradiation.I–V characteristics at Co/Si interface were undertaken to understand the irradiation effect on conduction mechanism at the interface. 相似文献
5.
Polyaniline thin films prepared by RF plasma polymerisation were irradiated with 92 MeV Si ions for various fluences of 1×1011, 1×1012 and 1×1013 ions/cm2. FTIR and UV-vis-NIR measurements were carried out on the pristine and Si ion irradiated polyaniline thin films for structural evaluation and optical band gap determination. The effect of swift heavy ions on the structural and optical properties of plasma-polymerised aniline thin film is investigated. Their properties are compared with that of the pristine sample. The FTIR spectrum indicates that the structure of the irradiated sample is altered. The optical studies show that the band gap of irradiated thin film has been considerably modified. This has been attributed to the rearrangement in the ring structure and the formation of CC terminals. This results in extended conjugated structure causing reduction in optical band gap. 相似文献
6.
S K Arora Ravi Kumar D Kanjilal G K Mehta S Khatua R Pinto Vijay Kumar A K Gupta 《Bulletin of Materials Science》1999,22(3):251-255
Effect of 250 MeV107Ag ion irradiation induced columnar defects on the noise properties of the YBCO superconductor in the normal and superconducting
state have been investigated. Magnitude of the spectral density of the noise is found to scale inversely with the frequency
and exhibit a quadratic dependence on the bias current confirming that the noise arises due to the resistance fluctuations.
The magnitude ofS
v has been found to decrease with decrease in temperature and shows a noise peak in the transition region. The noise performance
of these materials in the vicinity of the superconducting transition as well as in the normal state is found to improve by
an order of magnitude after irradiation with 250 MeV107Ag ions. The decrease in the magnitude of 1/f noise peak is due the irradiation induced enhanced flux pinning of the material which suppresses the flux motion induced
noise in the vicinity ofT
c. 相似文献
7.
Y2O3 thin films were in-situ deposited by ion beam sputtering on Si substrate. The influence of the deposition parameters are studied by X-ray diffraction, electrical measurements and high resolution transmission electron microscopy observations. The stress sate of the oxide layers is investigated by the sin2ψ method as a function of the deposition parameters and the post-annealing treatments. Oxygen ion beam assisted deposition process or post-annealing of as-deposited thin films lead to the same relaxation of the internal compressive stress within the oxide layer. An SiO2 layer sandwiched between Si and Y2O3 is always observed and should play a role both in the growing process and electrical properties of the MOS structure based on Y2O3 oxide layer. The results are interpreted in terms of diffusional process in the oxide, which are directly related to the temperature and the oxygen partial pressure during the growth process. 相似文献
8.
9.
研究了MEVVA离子注入机在Fe/Si系薄膜制备过程中产生的颗粒污染问题以及颗粒污染对薄膜质量带来的影响。选取不同制备条件下的Fe/Si薄膜,采用电子探针、透射电镜等分析手段对颗粒污染给Fe/Si薄膜所造成的影响进行了详细的分析和讨论。分析结果表明,MEVVA源离子注入机产生的颗粒污染主要包括Fe、Al、C、O等几种元素,这其中Fe和Al元素的污染较为严重。不同注入时期引入的颗粒对Fe/Si系薄膜的质量会产生不同程度的影响,针对不同的影响可以找到一些解决方法来克服薄膜质量下降的问题。 相似文献
10.
In this paper we compare the elastic energies obtained by tight-binding molecular dynamics simulations for several strained structures of β-FeSi2, corresponding to the most frequent epitaxial relationships ‘on’ and ‘in’ silicon. Our results confirm that, for coherent interfaces, the very common β-FeSi2(101) or (110)//Si(111) orientation generates a very large contribution to the elastic energy, due to the large misfit. Therefore, we suggest that the frequent nucleation of such epitaxial relationships in precipitates is provided by the correspondence of the two-dimensional crystal structure for the Si sites between Si(111) and β-FeSi2(101) or (110). We show it to be maintained even after misfit relaxation in the silicon matrix, as simulated by a large-scale molecular dynamics run. 相似文献
11.
In this work we investigate the surface and interfacial properties of Fe/Cr and Cr/Fe bilayers before and after annealing using Auger electron spectroscopy (AES). The roughness of the interface is also determined with the X-ray reflection method. The fitted values of inelastic mean free path λCr in Fe reproduce the calculated value for Cr in Fe well, whereas the values of λFe in Cr are significantly larger than the calculated ones, suggesting mutual segregation of atoms during growth. The low-energy range Auger spectra demonstrated that the MNN lines of Cr covered with Fe and Fe covered with Cr disappear after the deposition of 1 nm overlayer, this being an indication of continuous deposited film, but not excluding mixing at interfaces. The results of X-ray reflectometry measurements, which give the values of Fe/Cr and Cr/Fe roughness, are in accordance with this observation. The LMM Auger spectra of annealed samples showed that at the largest applied temperature, Cr diffuses into Fe, but the reverse effect of Fe diffusion into Cr is not observed. 相似文献
12.
A. Nagy A. Strahl H. Neuhuser S. Schrader I. Behrens E. Peiner A. Schlachetzki 《Materials Science and Engineering: A》2004,370(1-2):311-315
The vibrating reed technique with electro“static” excitation and optical detection has been applied to investigate thin layers of poly-phenylene-vinylene, deposited by spin coating onto microfabricated Si cantilevers, during temperature cycling programs between 90 and 540 K at a rate of 1 K/min. From the vibration frequencies the Young’s modulus of the film can be estimated to be about 10 MPa at room temperature in the precursor phase (if prepared from a solution in toluene), which increases by conversion to the conjugate bonded polymer to about 50 MPa. The temperature dependence of internal friction reveals the processes of γ relaxations (crankshaft motion of side branches in the precursor) and β-relaxation (movements of a few monomer blocks in the polymer chain), as well as peaks indicating the structural transformations during conversion, and possibly a glass transition in the amorphous precursor phase. After conversion only the β-relaxation persists. 相似文献
13.
14.
This paper investigates the effect of swift heavy ion (SHI) irradiation on surface morphology of Hydroxyapatite (HAp) thick films and modification in gas sensing characteristics. The HAp nanopowder is synthesized by wet chemical process and the thick films are prepared by screen printing technique. These films are irradiated with Ag7+ ions with energy of 100 MeV at different fluences ranging from 3 × 1010 to 3 × 1013 ions/cm2. X-ray diffraction and atomic force microscopy tools are employed to examine the phase and surface modification in HAp thick films due to swift heavy ion irradiation. The ion irradiation study shows that crystallinity decreases and grain size changes with increase in ion fluence. A precise study on gas sensing is carried out to confirm operating temperature of HAp thick film sensor to detect CO gas. Saturation region of the film with increasing gas concentration and other parameters such as response and recovery time are also investigated from the point of view of using HAp films as a sensor device. SHI irradiated HAp thick film shows enhancement in the gas response and saturation limit for CO gas. Furthermore, the irradiated HAp film shows fast response and recovery time for CO gas. The study concludes that nanoceramic HAp thick film is an excellent CO gas sensor at an operating temperature of 195 °C. 相似文献
15.
采用离子束溅射方法在Si衬底上制备Si/Ge多层膜,通过改变生长温度、溅射速率等因素得到一系列Si/Ge多层膜样品;通过X射线衍射、Raman散射等表征方法研究薄膜结构与生长条件的关系。在小束流(10mA)、室温条件下制备出界面清晰、周期完整的Si/Ge多层膜。 相似文献
16.
本文给出用等离子化学气相沉积 (PCVD)技术制备的SnO2 /Fe2 O3 双层薄膜结构的俄歇谱 (AES)剖面分析、透射电镜 (TEM)断面形貌和扫描电镜 (SEM)表面形貌的实验研究结果。AES剖面分析和TEM断面形貌图显示在SnO2 与Fe2 O3 界面区有一个约 35nm厚的过渡层存在 ,其质地松散。实验还发现这个界面过渡层的存在缓解了层间应力 ,增强了SnO2 薄膜的附着力 ,对该双层膜的气敏特性有明显的控制作用 ;但当SnO2 层厚大于 2 70nm时 ,其控制作用几乎完全消失 相似文献
17.
基于合金化的改性原理,以调整材料的长程有序度为改性思想,采用真空电弧熔炼/热压退火制备了四种Cr/Al复合合金化Fe3Si基有序合金。通过XRD,SEM,EPMA等对合金进行了表征,并采用长程有序参数定量表征了退火得到的有序相的有序程度。结果表明:四种不同成分的有序合金,具有不同的显微组织。随着Si含量降低合金有序度下降,且Cr/Al的复合效应对这一趋势起到了促进作用,使得具有相同Si含量的Fe65Si25Cr5Al5有序合金的有序度低于Fe3Si,分别为0.658和0.796。 相似文献
18.
采用酸碱共滴定法,以超顺磁性的纳米Fe3 O4为形核剂,成功制备 HAP/Fe3 O4、CS-HAP/Fe3 O4磁性纳米载体。利用透射电镜(TEM)、X 射线衍射仪(XRD)、傅里叶红外光谱分析仪(FT-IR)、振动样品磁强计(VSM)和 MTT 法对样品的显微结构、物相、磁性能和生物学性能进行了表征和分析。结果表明,所制备载体表现为超顺磁性,尺寸约为100 nm,均为20 nm左右的羟基磷灰石颗粒包裹20 nm 左右的Fe3 O4颗粒而成。其中双相载体中的 HAP 颗粒呈球形,三相载体中的 H AP颗粒呈短棒状。双相载体为1级细胞毒性反应,三相载体为0级毒性反应,具有促细胞增殖作用。 相似文献
19.
薄、轻、宽、强是人们对高效电磁波吸收材料的追求。用食品级柠檬酸铁与蔗糖经过水热反应,高温煅烧制备Fe/Fe_(3)C/Fe_(3)O_(4)@C磁性微球,并通过改变柠檬酸铁与蔗糖的摩尔比,探究柠檬酸铁的含量对复合材料吸波性能的影响,有效地调控电磁参数,从而优化阻抗匹配。实验结果表明,当柠檬酸铁与蔗糖的摩尔比为5∶3时,具有较好的吸波性能:当厚度为2.5 mm时,最小反射损耗为-50.17 dB,小于-10 dB的有效吸收频宽为3.52 GHz,优异的电磁波吸收性能主要得益于微球丰富的界面、孔状结构和Fe/Fe_(3)C/Fe_(3)O_(4)磁学性能的协同作用。 相似文献
20.
Thin layers of nanocrystalline FeSi2 embedded in Si structures have been formed by Fe implantation using a metal vapor vacuum arc (MEVVA) ion source under various implantation and thermal annealing conditions. The microstructures were studied in details and correlated with the photoluminescence (PL) properties. It is found that higher lattice coherence between the FeSi2 nanocrystals and the Si matrix is associated with better light emission efficiency. Multiple-cycle implantation schemes were introduced and it is shown that with appropriate process design the dose quenching effect can be suppressed to achieve light emission enhancement in higher dose samples. De-convolution of the PL spectra into two or three peaks was performed and their temperature and excitation power dependence were analyzed. The analysis results indicate that the 1.55-μm emission really originated from FeSi2 and that the emission peaks are likely donor- or accepted-level-related. MOS structures with the incorporation of implanted nanocrystalline FeSi2 were fabricated. Electroluminescence (EL) spectra from these devices showed two peak features of which one peak corresponds to FeSi2 emission and the other corresponds to enhanced Si band-edge emission. Clear room-temperature EL signals from these device structures were observed. A model is proposed to qualitatively understand the temperature dependence of the EL spectra. 相似文献