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1.
This paper investigates the anomalous and specific Raman modes present in Mn-doped ZnO thin films deposited using the magnetron co-sputtering method. To trace these peaks, we prepared Mn-doped ZnO films with different Mn concentrations by altering the sputtering power of the Mn target in a pure Ar or Ar + N2 sputtering atmosphere. A broad band observed in the Raman spectra of heavily Mn-doped ZnO films ranges from 500 to 590 cm− 1. This band involves the enhanced A1 longitudinal mode and activated silent modes of ZnO, as well as a characteristic mode of Mn2O3. Four anomalous Raman peaks at approximately 276, 510, 645 and 585 cm− 1 are present in pure and Mn-doped ZnO films deposited under the Ar + N2 sputtering atmosphere. The peaks at 276 cm− 1 and 510 cm− 1 may originate from the complex defects of Zni-NO and Zni-Oi, respectively, while the peak at approximately 645 cm− 1 could be due to a complex defect of Zni coupled with both the N and Mn dopants. The results of this study suggest classifying the origins of anomalous and specific Raman peaks in Mn-doped ZnO films into three major types: structural disorder and morphological changes caused by the Mn dopant, Mn-related oxides and intrinsic host-lattice defects coupled with/without the N dopant. 相似文献
2.
Amorphous B-C-N films were fabricated on silicon (100) substrates using radio frequency reactive magnetron sputtering technique with variable N2/Ar flow ratios. The structures, chemical bonding and mechanical properties were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. We found that the N concentration is insensitive to the increment of N2/Ar flow ratio while the B concentration decreases and C concentration increases. All B-C, C-N, and B-N bond contents increase as the N2/Ar flow ratio varies from 1/10 to 5/10. Further improving the N2/Ar flow ratio will promote N atoms prior to bonding with C, resulting in decreased B-C and increased C-N bond content, respectively. The changes of bond content lead to a shift of the main peaks of B1s, C1s, and N1s spectra toward higher binding energies. The hardness of B-C-N thin films is almost invariant with the N2/Ar flow ratio. 相似文献
3.
High quality Tl2Ba2CaCu2O8 (Tl-2212) superconducting thin films are prepared on both sides of 2 in. LaAlO3(0 0 1) substrates by off-axis magnetron sputtering and post-annealing process. XRD measurements show that these films possess pure Tl-2212 phase with C-axis perpendicular to the substrate surface. The thickness unhomogeneity of the whole film on the 2 in. wafer is less than 5%. The superconducting transition temperatures Tcs of the films are around 105 K. At zero applied magnetic field, the critical current densities Jcs of the films on both sides of the wafer were measured to be above 2 × 106 A/cm2 at 77 K. The microwave surface resistance Rs of film was as low as 350 μΩ at 10 GHz and 77 K. In order to test the suitability of Tl-2212 thin films for passive microwave devices, 3-pole bandpass filters have been fabricated from double-sided Tl-2212 films on LaAlO3 substrates. 相似文献
4.
Takahiro Itoh 《Vacuum》2007,81(9):1068-1076
The growth process of CuO and Cu2O thin films on MgO(0 0 1) substrates by reactive dc-magnetron sputtering was studied by reflection high-energy electron diffraction (RHEED) and atomic-force microscopy (AFM). The RHEED pattern and AFM image showed that (1) three-dimensional Cu(0 0 1) islands grew on MgO under the nonreactive sputtering condition, (2) CuO(1 1 1) was deposited layer by layer on MgO at 400 °C under the reactive sputtering condition, and (3) the film deposited at 600 °C in the initial growth stage was composed of three-dimensional Cu islands because O2 gas could not be incorporated into them due to the low sticking coefficient of O2 on MgO under the reactive sputtering condition. The layer-by-layer CuO(1 1 1) thin-film growth process is discussed from the viewpoint that Cu and oxygen species are supplied in stoichiometry onto the MgO substrate to form CuO thin-film crystals while maintaining minimum interfacial energy between CuO and MgO. 相似文献
5.
Ar+ assisted carbidization of Mo nanoparticles supported on TiO2 (1 1 0) is studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In order to activate the diffusion of carbon into the bulk of Mo nanoparticles we applied Ar ions (1 keV) during the exposure of C2H4. XPS exhibited that the decomposition of C2H4 at 850 K accompanied by ion bombardment results in an almost complete carbidization of nanocrystalline Mo while this treatment performed without ion bombardment results only in the carbidization of the particle surface. The modification of the crystallinity of the Mo-carbide particles was deduced from STM measurements. 相似文献
6.
A one-pot approach to hardening ZrO2-based films prepared by the sol-gel method is presented. It entails performing the sintering in a nitrogen atmosphere, instead of in the conventional air atmosphere. It is shown that, when the sintering temperature is high enough, gas nitriding takes place in the ceramic film, leading to a 15% increase in its hardness. This occurs because more nitrogen solutes are incorporated into the crystal lattice of the 3YSZ host, forming solid solutions (i.e., greater solid-solution-effect hardening). The proposed gas nitriding is simple and cost-effective, and adds no additional steps to the processing routine. This suggests that it may have an important role to play in the fabrication of hard ceramic films from liquid precursors. 相似文献
7.
Aluminum rich oxynitride thin films were prepared using pulsed direct current (DC) magnetron sputtering from an Al95.5Cr2.5Si2 (at.%) target. Two series of films were deposited at 400 °C and 650 °C by changing the O2/(O2 + N2) ratio in the reactive gas from 0% (pure nitrides) to 100% (pure oxides). The films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and nanoindentation. The results showed the existence of three different regions of microstructure and properties with respect to the oxygen concentration. For the samples deposited at 650 °C in the nitrogen rich region (O2/(O2 + N2) ≤ 0.08), the formation of the h-AlN (002) and Al-N bond were confirmed by XRD and XPS measurements. The hardness of the films was around 30 GPa. In the intermediate region (0.08 ≤ O2/(O2 + N2) ≤ 0.24), the presence of an amorphous structure and the shifting of the binding energies to lower values corresponding to non-stoichiometric compounds were observed and the hardness decreased to 12 GPa. The lowering of mechanical properties was attributed to the transition of the clean target to the reacted target under non-steady state deposition conditions. In the oxygen rich region (0.24 ≤ (O2/(O2 + N2) ≤ 1), the existence of α-Al2O3-(113), α-Al2O3-(116) and Al-O bonds confirmed the domination of this phase in this region of deposition and the hardness increased again to 30-35 GPa. Films deposited at 400 °C showed the same behavior except in the oxygen rich region, where hardness remains low at about 12-14 GPa. 相似文献
8.
Takahiro Itoh 《Vacuum》2007,81(7):904-910
Copper oxide films deposited on MgO(0 0 1) substrates by reactive magnetron sputtering under the metal-mode condition were studied by X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED) analyses for structural analysis, and X-ray-excited Auger electron spectroscopy (XAES) for chemical bonding analysis. CuO(1 1 1) thin films grew from their initial growth stage maintaining the same crystallinity on MgO(0 0 1) substrates at 400°C. When the substrate temperature was increased to 600 °C, the as-sputtered films comprise Cu(0 0 1), amorphous Cu2O phase, and Cu2O(0 0 1) phase. The Cu(0 0 1) phase was observed at initial growth stage. This is probably because O2 gas molecules could not sufficiently stick to the MgO substrate at 600 °C. Single phase of Cu2O(0 0 1) was obtained by the cooling of the as-sputtered films in O2 atmosphere. The growth of single phase Cu2O(0 0 1) is considered as a solid-phase heteroepitaxial growth on MgO(0 0 1) surface, which was caused by incorporating O2 gas into the as-sputtered films. 相似文献
9.
Hajime Kawakami 《Vacuum》2007,82(1):95-99
Thin-film growth process of InTaO4 on MgO substrates held at 700 °C is analyzed on the basis of the thickness dependence of the structure determined by X-ray diffraction analysis and the composition determined by X-ray photoemission spectroscopy. Monoclinic InTaO4 thin film grows at thicknesses above a critical value, while the amorphous phase grows at thicknesses below the critical thickness because the amount of In becomes insufficient to form the respective monoclinic structure. The In atoms are re-evaporated from the MgO surface at the initial growth stage. The growing films possibly comprise amorphous TaOx. The In atoms start to be incorporated into the growing films due to the reduction of re-evaporation of In atoms. This leads to the start of the interaction with Ta and O atoms resulting in the formation of InTaO4. The critical thickness to form a crystalline InTaO4 film is controlled by adjusting the incoming flux of In atoms. 相似文献
10.
Vinit O. Todi Bojanna P. ShantheyandaRavi M. Todi Kalpathy B. SundaramKevin Coffey 《Materials Science and Engineering: B》2011,176(12):878-882
We present the deposition and optical characterization of amorphous thin films of boron carbonitride (BCN). The BCN thin films were deposited in a radio frequency magnetron sputtering system using a B4C target. Films of different compositions were deposited by varying the ratio of argon and nitrogen gas in the sputtering ambient. X-ray photoelectron spectroscopy was used to perform surface characterization of the deposited films and a change in composition with nitrogen flow ratio was observed. The effect of gas flow ratios on the optical properties of the films was also investigated. It was found that the transmittance of the films increases with nitrogen incorporation. The optical band gap of the films ranged from 2.0 eV to 3.1 eV and increased with N2/Ar gas flow ratio except at the highest ratio. 相似文献
11.
La0.67Ca0.33MnO3 (LCMO) thin films were successfully fabricated by a DC magnetron sputtering technique on Si (1 0 0) substrates from chemically synthesized compacted powders. Powders of proper stochiometry composites were synthesized by a novel chemical technique [D.R. Sahu, B.K. Roul, P. Pramanik, J.L. Huang, Physica B 369 (2005) 209] and were found to be nanosized (≈40-50 nm). The sinterability of the powders were improved significantly due to their large surface area with a reduction of sintering temperature (up to 500 °C) as compared to the powders prepared by other solid-state reaction route. Bulk LCMO targets were prepared and preliminary structural and magnetic properties of target were investigated for colossal magnetoresistance (CMR) properties. Films deposition parameters like DC power, gas flow rate, deposition time, etc., were critically optimized to achieve desired thickness of film using above LCMO target by DC magnetron sputtering. LCMO films fabricated on Si (1 0 0) substrates showed enhanced magnetoresistance (MR) at low temperature. Maximum MR of about 1000% was observed at 100 K. Paramagnetic to ferromagnetic transitions were observed in films below room temperature and were found at approximately 240 K. However, as compared to bulk target prepared by a chemical route, it was found that Curie temperature (Tc) and MR response of bulk target were higher than the thin films. Preliminary point chemical analysis revealed the deficiency of Ca2+ ions in CMR films. 相似文献
12.
The structure and composition of nanostructured multilayer V-B-N films, deposited by high-frequency magnetron sputtering of a composite VB2 target in a gaseous mixture of argon and nitrogen, were studied by means of electron spectroscopy, X-ray diffraction and secondary ion mass-spectroscopy. The influence of the percentage ratio of nitrogen on the process of formation of films was investigated. On high-frequency reactive magnetron sputtering the composition of a superficial layer of a target changes. The influence of this change on structure and composition of coverings was described. The method of synthesis of multilayer films of borides and nitrides of vanadium is offered. Formation mechanisms of boride and nitride films are discussed. 相似文献
13.
Polycrystalline TiN/SiNx multilayer films are deposited using reactive magnetron sputtering Ti and Si, respectively, discharging a mixture of N2 and Ar gas with different N2/Ar gas flow ratios, and their structures and mechanical properties are characterized by X-ray reflectivity (XRR), X-ray diffraction (XRD) and nanoindentation. It is found that when the N2/Ar gas flow ratio is low, the interface between TiN and SiNx layer for the obtained TiN/SiNx film is sharp and the preferred orientation for TiN layer is TiN (200). In contrast, when the N2/Ar gas flow ratio is high, the interface becomes rough and the preferred orientation for TiN layer changes to TiN (111). Nanoindentation experiments exhibit that the TiN/SiNx film with a TiN (111) preferred orientation is harder than that with a TiN (200) preferred orientation, and all films have nano-scale fracture characteristics. 相似文献
14.
The effect of Al2O3 content on the structure, electrical properties, magnetic properties, and interparticle exchange interactions of (Fe65Co35)1 − x(Al2O3)x films with Al2O3 volume fractions x ranging from 0 to 0.50 was systematically investigated. Among the films with x between 0 and 0.25, the lowest coercivity of 0.56 kA/m was achieved in the (Fe65Co35)0.82(Al2O3)0.18 film. This is ascribed to the strongest exchange interactions between the Fe65Co35 nanoparticles in this film. Combined with the microstructure analysis of the (Fe65Co35)1 − x(Al2O3)x films, the modified Herzer's model was extended to interpret the variation of the coercivity with x and analyze the effect of the exchange interactions between the Fe65Co35 nanoparticles on the magnetic softness. The remanence curves confirm the existence of the exchange interactions and reveal the evolution of the exchange interaction strength with Al2O3 content. 相似文献
15.
Crystalline β-BBO layers have been successfully prepared on (0 0 1)-oriented Sr2+-doped α-BBO substrates using vapor transport equilibration technique. The layers were characterized by X-ray diffraction, X-ray rocking curve and transmission spectra. The present results manifest that the VTE treatment time and powder ratio are important factors on the preparation of β-BBO layers. β-BBO layers with a highly (0 0 l) preferred orientation were obtained according to XRD profiles. The full width at half-maximum of the rocking curve for the layer is as low as about 1000 in., which shows the high crystallinity of the layer. These results reveal the possibility of fabricating β-BBO (0 0 1) layers on (0 0 1)-oriented Sr2+-doped α-BBO substrates by VTE. 相似文献
16.
Zirconium nitride (ZrN) films were deposited by ion beam sputtering technique on stainless steel 304 substrates using a mix of (Ar+N2) gas. In this paper, the effects of N2/(N2+Ar) flow ratio (F(N2)) and substrate temperature on the microstructure and microscopic properties of the deposited films were investigated. The phase and the morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively; moreover, the composition depth profile of ZrN was obtained using secondary ion mass spectroscopy (SIMS). In a wide range of F(N2) (10-54%), the intensity of (1 1 1) peak increased which was the preferred orientation, while for F(N2) more than 54% the ZrN peak intensity was decreased and the amorphous structure was formed at 95%. The XRD patterns presented a texture change due to the processing temperature, which was varied within the range 200-550 °C. At 400 °C, the (1 1 1) crystalline plane intensity was higher than the other ones, leading to the presence of a preference for this orientation. Good planarity of the deposited films was confirmed by SEM, it did not reveal any undulations, fractures, or cracking. The Vickers micro-hardness tester with a load of 25 g was used to measure the hardness of the films. The results showed that the structural and mechanical properties were strongly influenced by nitrogen ratio and substrate temperature. 相似文献
17.
Seung-Hyun Cho 《Materials Letters》2007,61(1):256-258
Powders of a Pb(Zn1 / 2W1 / 2)O3-introduced BaTiO3-PbTiO3 system were prepared. A two-step calcination route of a B-site precursor method was employed to promote perovskite formation. The overall effects of the Pb(Zn1 / 2W1 / 2)O3 incorporation on changes in crystalline aspects as well as dielectric properties were explored. 相似文献
18.
Using RF magnetron sputtering, we have successfully grown (1 1 0) orientated La0.7Sr0.3MnO3 (LSMO) films on Si(0 0 1) wafers using SrMnO3 (SMO) as a template layer. The X-ray diffraction (XRD) patterns of the SMO/Si heterostructures indicate that SMO grows along the (1 1 0) orientation, the orientation relationship between the SMO thin film and the Si (0 0 1) substrate being given by (0 1 1)SMO∣∣(0 0 1)Si and [01]SMO∣∣[0 1 0]Si. From the XRD patterns of the LSMO/SMO/Si heterostructures, we find that with an increase of substrate temperature, the required thickness of SMO, which plays an effective role of tuning the preferential orientation of LSMO, will decrease at first and then increase. It is thought that this originates from the fact that the crystallization of SMO is not perfect at low temperatures whereas too high a temperature results in reaction and diffusion at the interface of the two layers. 相似文献
19.
Ning LiYoshio Abe Midori KawamuraKyung Ho Kim Tsutomu Suzuki 《Thin solid films》2012,520(16):5137-5140
Hydrated ZrO2 thin films were prepared by reactive sputtering in O2, H2O, and H2O + H2O2 mixed gas, and the effect of the sputtering atmosphere on ion conductivity of the films was investigated. The results showed that the films deposited in O2 gas exhibited poor ion conductivity; however, the ion conductivities of the films deposited in the other two kinds of atmosphere were similar and 300-500 times higher than that of the films deposited in O2 gas. It was indicated that the higher ion conductivity of the films was caused by lower film density and higher water content. 相似文献
20.
Chung-Chieh Chang Jiu-Yong Luo Kuo-Wei Yeh Chia-Hao Hsu Chung-Ting Ke Ming-Jye Wang 《Thin solid films》2010,519(5):1552-1557
In this study we demonstrate a new composite oxide thin films of (MoO3)1 − x(V2O5)x, x = 0, 0.01, 0.03, and 0.05, fabricated by pulsed laser deposition (PLD). The performance of platinum (Pt) catalyst activated hydrogen gas sensor with modified (MoO3)1 − x(V2O5)x thin films were investigated. The thickness of the (MoO3)1 − x(V2O5)x thin film is about 600-650 nm and its surface has a uniform morphology. Our results show that the gasochromic sensors prepared by (MoO3)0.99(V2O5)0.01 thin film exhibited excellent hydrogen sensibility. The response and recovery time are in the range of 9-15 min for coloration and bleaching at room temperature under H2 atmosphere. The results also show that (MoO3)1 − x(V2O5)x/Pt (x = 0.01, 0.03, 0.05) thin films perform better gasochromic capability than the pristine MoO3/Pt sample. 相似文献