Effect of the substrate surface condition on the Ni(thin film)/SiC(0001) interfacial reaction

2007 ◽  
Vol 22 (9) ◽  
pp. 2522-2530 ◽  
Author(s):  
Cory R. Dean ◽  
Kevin Robbie ◽  
Lynnette D. Madsen

The effect of the substrate surface, structure, and chemistry on the interfacial interaction in Ni(thin film)/SiC was examined, with a focus on the recently discovered formation of a nickel intercalated graphite phase. Very thin Ni films (∼7 nm) were deposited onto heated 6H–SiC(0001) substrates prepared with: (i) an oxide layer, (ii) a surface reconstruction, and (iii) a pristine surface (no oxide and no reconstruction), followed by further annealing. Characterization using x-ray diffraction and atomic force microscopy revealed remarkable differences between the samples in terms of both surface morphology and crystallography. Nickel silicides were present in all samples; however, the phase composition differed depending on sample preparation. Furthermore, the pristine surface was the only one that clearly promoted the growth of the nickel graphite intercalation compound (Ni-GIC).

1999 ◽  
Vol 562 ◽  
Author(s):  
C. Liu ◽  
L. Shen ◽  
H. Jiang ◽  
D. Yang ◽  
G. Wu ◽  
...  

ABSTRACTThe Ni80Fe20/Fe50Mn50,thin film system exhibits exchange bias behavior. Here a systematic study of the effect of atomic-scale thin film roughness on coercivity and exchange bias is presented. Cu (t) / Ta (100 Å) / Ni80Fe20 (100 Å) / Fe50Mno50 (200 Å) / Ta (200 Å) with variable thickness, t, of the Cu underlayer were DC sputtered on Si (100) substrates. The Cu underlayer defines the initial roughness that is transferred to the film material since the film grows conformal to the initial morphology. Atomic Force Microscopy and X-ray diffraction were used to study the morphology and texture of the films. Morphological characterization is then correlated with magnetometer measurements. Atomic Force Microscopy shows that the root mean square value of the film roughness exhibits a maximum of 2.5 Å at t = 2.4 Å. X-ray diffraction spectra show the films are polycrystalline with fcc (111) texture and the Fe50Mn50 (111) peak intensity decreases monotonically with increasing Cu thickness, t. Without a Cu underlayer, the values of the coercivity and loop shift are, Hc = 12 Oe and Hp = 56 Oe, respectively. Both the coercivity and loop shift change with Cu underlayer thickness. The coercivity reaches a maximum value of Hc= 36 Oe at t = 4 Å. The loop shift exhibits an initial increase with t, reaches a maximum value of HP = 107 Oe at t = 2.4 Å, followed by a decrease with greater Cu thickness. These results show that a tiny increase in the film roughness has a huge effect on the exchange bias magnitude.


Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 373 ◽  
Author(s):  
Roland Resel ◽  
Markus Koini ◽  
Jiri Novak ◽  
Steven Berkebile ◽  
Georg Koller ◽  
...  

A 30 nm thick quinquephenyl (5P) film was grown by molecular beam deposition on a Cu(110)(2×1)O single crystal surface. The thin film morphology was studied by light microscopy and atomic force microscopy and the crystallographic structure of the thin film was investigated by X-ray diffraction methods. The 5P molecules crystallise epitaxially with (201)5P parallel to the substrate surface (110)Cu and with their long molecular axes parallel to [001]Cu. The observed epitaxial alignment cannot be explained by lattice matching calculations. Although a clear minimum in the lattice misfit exists, it is not adapted by the epitaxial growth of 5P crystals. Instead the formation of epitaxially oriented crystallites is determined by atomic corrugations of the substrate surface, such that the initially adsorbed 5P molecules fill with its rod-like shape the periodic grooves of the substrate. Subsequent crystal growth follows the orientation and alignment of the molecules taken within the initial growth stage.


2008 ◽  
Vol 15 (06) ◽  
pp. 787-791
Author(s):  
PEI ZHAO ◽  
RENG WANG ◽  
DINGQUAN LIU ◽  
FENGSHAN ZHANG ◽  
WEITAO SU ◽  
...  

The effects of the roughness of ZnS underlayer on the microstructure, optical, and electrical properties of nanometer Ag thin film have been investigated in this paper. Nanometer Ag thin films in glass/ ZnS /7.5 nm Ag /30 nm ZnS stacks have been deposited and analyzed. In the stacks, the underlayers of ZnS have been sputtered with various thicknesses to generate various surface roughnesses. The X-ray diffraction (XRD) has been used to study the crystal structure of Ag films. The surface topography and the roughness of ZnS underlayer have been analyzed by atomic force microscopy. The sheet resistant will become larger as the increasing of the roughness. The optical constants can be derived by fitting the transmission and reflectance spectrum. From optical constants comparison of Ag films, with the surface of the stack becoming rougher, it was found that the refractive index will increase but the extinction coefficient will decrease.


2015 ◽  
Vol 814 ◽  
pp. 39-43 ◽  
Author(s):  
Lei Lei Chen ◽  
Hong Mei Deng ◽  
Ke Zhi Zhang ◽  
Ling Huang ◽  
Jian Liu ◽  
...  

Cu2MnSnS4 thin film was successfully prepared by a sol-gel technique on soda lime glass substrate from metal salts and thiourea. The structural and morphological properties of the fabricated film were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy. The combination of the X-ray diffraction results and Raman spectroscopy reveal that this obtained layer is composed by Cu2MnSnS4 phase and has a stannite structure with preferential orientation along the (112) direction. The scanning electron microscopy and atomic force microscopy results show that the synthesized thin film is smooth and compact without any visible cracks or pores. The band gap of the Cu2MnSnS4 thin film is about 1.29 eV determined by the UV-vis-NIR absorption spectra measurement, which indicates it has potential applications in solar cells.


1994 ◽  
Vol 341 ◽  
Author(s):  
J. J. Kingston ◽  
D. K. Fork ◽  
F. Leplingard ◽  
F. A. Ponce

AbstractThin-film waveguides of LiNbO3 have been grown on Al2O3-c by off-axis rf magnetron sputtering. The films have been characterized optically by prism coupling measurements, crystallographically by x-ray diffraction, and morphologically by atomic force microscopy. We find that optical losses can be dominated by scattering from large outgrowths that litter the surface of the film. These outgrowths are c− grains imbedded in a c+ matrix. Although some grains nucleate c−, others have their polarity reversed from c+ to c− after nucleation. A model will be presented to explain the preferential nucleation of c+ grains on Al2O3-c. The c− grains grow much faster than the c+ ones because of attractive coulombic forces between the c− grains and the ionized Li and Nb species in the sputter plume.


2010 ◽  
Vol 445 ◽  
pp. 160-163
Author(s):  
Shigeki Sawamura ◽  
Naonori Sakamoto ◽  
De Sheng Fu ◽  
Kazuo Shinozaki ◽  
Hisao Suzuki ◽  
...  

Thermal stability of bottom electrode thin films (La0.5Sr0.5)CoO3 (LSCO) and (La0.6Sr0.4)MnO3 (LSMO) were investigated. The crystallization and surface morphology of the heterostructure were characterized using x-ray diffraction and atomic force microscopy. Resistivity of the LSCO thin film was 25 cm. However, the resistivity of LSCO thin film increases sharply with annealing temperature. The LSMO thin film has high resistivity (100 mcm). The film does not decompose after thermal processing at 900 °C. To confirm thermal stability, we examined the effect of post annealing at various temperatures on the morphology and resistivity. Results showed that LSMO has higher thermal stability than that of LSCO.


1999 ◽  
Vol 595 ◽  
Author(s):  
Olivier Parillaud ◽  
Volker Wagner ◽  
Hans-Jörg Bühlmann ◽  
François Lelarge ◽  
Marc Ilegems

AbstractWe present preliminary results on gallium nitride growth by HVPE on C-plane sapphire with 2, 4 and 6 degrees misorientation towards M and A directions. A nucleation GaN buffer layer is deposited prior the growth by MOVPE. Surface morphology and growth rates are compared with those obtained on exact C-plane oriented sapphire, for various growth conditions. As expected, the steps already present on the substrate surface help to initiate a directed step-flow growth mode. The large hillocks, which are typical for HVPE GaN layers on (0001) sapphire planes, are replaced by more or less parallel macro-steps. The width and height of these steps, due to step bunching effect, depend directly on the angle of misorientation and on the growth conditions, and are clearly visible by optical or scanning electron microscopy. Atomic force microscopy and X-ray diffraction measurements have been carried out to quantify the surface roughness and crystal quality.


2010 ◽  
Vol 10 (1) ◽  
pp. 8-11 ◽  
Author(s):  
Anuar Kassim ◽  
Tan WeeTee ◽  
Dzulkefly Kuang Abdullah ◽  
Atan Mohd. Sharif ◽  
Ho SoonMin ◽  
...  

FeS2 thin films have been deposited by using low cost chemical bath deposition technique. The films obtained under deposition parameters such as bath temperature (90 °C), deposition period (90 min), electrolyte concentration (0.15 M) and pH of the reactive mixture (pH 2.5). The thin films were characterized using X-ray diffraction and atomic force microscopy in order to study the structural and morphological properties. The band gap energy, transition type and absorption properties were determined using UV-Vis Spectrophotometer. X-ray diffraction displayed a pattern consistent with the formation of an orthorhombic structure, with a strong (110) preferred orientation. Atomic force microscopy image showed the substrate surface is well covered with irregular grains. A direct band gap of 1.85 eV was obtained according to optical absorption studies.   Keywords: Iron sulfide, X-ray diffraction, chemical bath deposition, thin films


2016 ◽  
Vol 848 ◽  
pp. 440-445
Author(s):  
Liang Chen ◽  
Jin Xiang Deng ◽  
Hong Li Gao ◽  
Qian Qian Yang ◽  
Le Kong ◽  
...  

CH3NH3PbI3 thin film was deposited by a dual-source evaporation system under high vacuum (∼10−4 Pa). The crystallographic phase was analyzed by X-ray diffraction and confirmed as the perovskite structure. The optical properties of the thin film have been investigated in the spectral range 300-1800 nm. The analysis of the absorption coefficient () reveals direct allowed transition with corresponding energy 1.58 eV. The surface morphology of the film was characterized by atomic force microscopy (AFM). The observed features exhibited by CH3NH3PbI3 give a vital chance to explore its application for various optoelectronic devices. To see its other potential utility, Al/CH3NH3PbI3 /ITO Schottky diodes were fabricated. Based on the analyzing the I-V measurement for the Al/CH3NH3PbI3/ ITO device, the basic device parameters such as barrier height and ideality factor were determined. At the low-voltage region, the current conduction in the device is ohmic type. The charge transport phenomenon appears to be space charge limited current (SCLC) at higher-voltage regions.


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