Electrical conduction of intrinsic grain and grain boundary in Mn-Co-Ni-O thin film thermistors: Grain size influence

2011 ◽  
Vol 110 (9) ◽  
pp. 093708 ◽  
Author(s):  
L. He ◽  
Z. Y. Ling
1985 ◽  
Vol 63 (6) ◽  
pp. 716-718 ◽  
Author(s):  
S. Chandrasekhar ◽  
S. Martinuzzi ◽  
F. Z. Nataren

For low Zn concentrations i.e., x < 0.1, the performance of the Cd1−xZnxS–Cu2S solar cells can be improved by reducing the grain-boundary recombination. This has been achieved by growing well-oriented, homogeneous, ternary compound films.It was found that the Cd1−xZnxS films grown on the polycrystalline CdS films achieved the same larger grain size as that of the base layer. These films had fewer misorientations and had a unimodal grain-size distribution. There is a continuity in the crystallites from the CdS base to the Cd1−xZnxS overlayer, and the bifilms thus grown are less resistive than Cd1−xZnxS single layers.


2021 ◽  
Vol 67 (2 Mar-Apr) ◽  
pp. 263
Author(s):  
T. O. Daniel ◽  
U. E. Uno ◽  
K. U. Isah ◽  
U. Ahmadu

This study is focused on the investigation of SnS thin film for transistor application. Electron trap which is associated with grain boundary effect affects the electrical conductivity of SnS semiconductor thin film thereby militating the attainment of the threshold voltage required for transistor operation. Grain size and grain boundary is a function of a semiconductor’s thickness. SnS semiconductor thin films of 0.20, 0.25, 0.30, 0.35, 0.40 μm were deposited using aerosol assisted chemical vapour deposition on glass substrates. Profilometry, Scanning electron microscope, Energy dispersive X-ray spectroscopy and hall measurement were used to characterise the composition, microstructure and electrical properties of the SnS thin film.  SnS thin films were found to consist of Sn and S elements whose composition varied with increase in thickness. The film conductivity was found to vary with grain size and grain boundary which is a function of the film thickness. The SnS film of 0.4 μm thickness shows optimal grain growth with a grain size of 130.31 nm signifying an optimum for the as deposited SnS films as the larger grains reduces the number of grain boundaries and charge trap density which allows charge carriers to move freely in the lattice thereby causing a reduction in resistivity and increase in conductivity of the films which is essential in obtaining the threshold voltage for a transistor semiconductor channel layer operation. The carrier concentration of due to low resistivity of 3.612 ×105 Ωcm of 0.4 μm SnS thin film thickness is optimum and favours the attainment of the threshold voltage for a field effect transistor operation hence the application of SnS thin film as a semiconductor channel layer in a field effect transistor.


2009 ◽  
Vol 7 ◽  
pp. 59-68 ◽  
Author(s):  
Yuri S. Kaganovsky ◽  
Lyudmila N. Paritskaya ◽  
V.V. Bogdanov

The kinetics of lateral Cu6Sn5 and Cu3Sn phase propagation induced by grain boundary (GB) interdiffuson in thin-film diffusion couples Cu-Sn were studied in a temperature range 160-180oC by optical microscopy, AFM, SEM, and energy-dispersive X-ray spectroscopy (EDS). Nano-grained Cu and Sn films were sequentially deposited on glass substrates with 5 – 20 µm overlap. To prevent surface diffusion and thus separate GB-diffusion contribution into kinetics of phase propagation, the surfaces of diffusion couples were covered by a thin (20 – 40 nm) carbon layer. It was found that the rates of lateral Cu6Sn5 and Cu3Sn phase spreading in thin-film couples exceed several times the spreading rates of the same phases over the surface of coarse-grained samples and 50 – 70 times exceed the rates in the bulk of massive samples. Kinetics of lateral phase spreading both in thin-film and in massive diffusion couples obeys parabolic law. Similarly to A and B regimes for GB tracer diffusion, A and B regimes of GB reactive diffusion were found in the spreading Cu3Sn phase. The kinetics of the phase propagation turned out independent of the film thickness (in the range 40 – 200 nm) if the films possessed similar grain size, whereas the kinetics was rather sensitive to the grain size and GB structure. Theoretical analysis of the phase propagation kinetics accelerated by GB diffusion has been done and the phase propagation rates have been calculated. By comparison experimentally measured phase propagation rates with the calculated ones we determined the GB diffusion coefficients of Sn in both growing phases.


Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.


Author(s):  
Frastica Deswardani ◽  
Helga Dwi Fahyuan ◽  
Rimawanto Gultom ◽  
Eif Sparzinanda

Telah dilakukan penelitian mengenai pengaruh konsentrasi doping karbon pada lapisan tipis TiO2 yang ditumbuhkan dengan metode spray terhadap struktur kristal dan morfologi TiO2. Hasil karakterisasi SEM menunjukkan bahwa penambahan doping karbon dapat meningkatkan ukuran butir. Lapisan TiO2 doping karbon 8% diperoleh ukuran butir terbesar adalah 1.35 μm, sedangkan ukuran tekecilnya adalah 0.45 μm. Sementara itu, untuk lapisan tipis TiO2 didoping karbon 15% memiliki ukuran butir terbesar yaitu 1.76 μm dan terkecil 0.9 μm. Hasil XRD menunjukkan seluruh puncak difraksi lapisan tipis TiO2 dengan doping karbon 8% dan 15% merupakan TiO2 anatase. Ukuran kristal lapisan TiO2 didoping karbon 8% diperoleh sebesar 638,08 Å dan untuk pendopingan 15% karbon ukuran kristal lapisan tipis TiO2 adalah 638,09 Å, hal ini menunjukkan ukuran kristal kedua sampel tidak mengalami perubahan yang signifikan.   TiO2 thin film with carbon doping has been successfully grown by spray method. The research on the effect of carbon doping on crystal structure and morfology of TiO2 has been prepared by varying carbon concentration (8% and 15% carbon). Analysis of SEM showed that the addition of carbon may increase the grain size. Thin film of TiO2 doped carbon 8% has the largest grain size 1.35 μm, while the smallest grain size is 0.45 μm. Meanwhile, for thin film TiO2 doped carbon 15% has the largest grain size 1.76 μm and smallest 0.9 μm. The XRD results showed the entire diffraction peak of thin film TiO2 doped carbon 8% and 15% were TiO2 anatase. The crystal size of thin film TiO2 doped carbon 8% was obtained at 638.08 Å and for thin film TiO2 doped carbon 15% the crystalline size of TiO2 thin film was 638.09 Å, this shows that the crystal size of both samples did not change significantly.    


1987 ◽  
Author(s):  
K. Sugihara ◽  
M. S. Dresselhaus

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Weiguang Zhang ◽  
Jijun Li ◽  
Yongming Xing ◽  
Xiaomeng Nie ◽  
Fengchao Lang ◽  
...  

SiO2 thin films are widely used in micro-electro-mechanical systems, integrated circuits and optical thin film devices. Tremendous efforts have been devoted to studying the preparation technology and optical properties of SiO2 thin films, but little attention has been paid to their mechanical properties. Herein, the surface morphology of the 500-nm-thick, 1000-nm-thick and 2000-nm-thick SiO2 thin films on the Si substrates was observed by atomic force microscopy. The hardnesses of the three SiO2 thin films with different thicknesses were investigated by nanoindentation technique, and the dependence of the hardness of the SiO2 thin film with its thickness was analyzed. The results showed that the average grain size of SiO2 thin film increased with increasing film thickness. For the three SiO2 thin films with different thicknesses, the same relative penetration depth range of ~0.4–0.5 existed, above which the intrinsic hardness without substrate influence can be determined. The average intrinsic hardness of the SiO2 thin film decreased with the increasing film thickness and average grain size, which showed the similar trend with the Hall-Petch type relationship.


2011 ◽  
Vol 682 ◽  
pp. 211-216
Author(s):  
Rong Zhu ◽  
Jin Qiang Liu ◽  
Jing Tao Wang ◽  
Ping Huang ◽  
Yan Jun Wu ◽  
...  

Equal channel angular pressing (ECAP) has been used to refine the grain size of Mg-12Gd-3Y-0.5Zr billet at about 400°C because it lacks sufficient ductility at low temperatures. However, <0001> peak intensity is oriented about 50º from the extrusion direction, which facilitates the basal slip, and decreases the yield strength. We have employed conventional extrusion at 300°C following ECAP to modify the texture in hard orientation. This two-step process makes use of two strengthening mechanisms a) grain boundary strengthening due to small grain size, and (b) texture strengthening due to grains in hard orientation. The samples processed by the two-step show the yield and ultimate strength to 283 and 308 MPa, respectively. Moreover, the activation of <c+a> slip and fine grains resulted from the ECAP helped to maintain a good ductility even after significant straining from conventional extrusion.


2004 ◽  
Vol 11 (02) ◽  
pp. 173-178 ◽  
Author(s):  
WEN LI ◽  
D. Y. LI

The Kelvin probe is a sophisticated instrument which is very sensitive to changes in surface conditions, such as deformation, texture, phase transformation and contamination. Efforts have been made to use this technique to diagnose wear. In this study, the effect of the grain boundary (GB) on the electron work function (EWF) was examined with the aim of investigating the contribution of changes in grain size to total changes in the EWF during wear. Copper and aluminum were studied as examples. It was demonstrated that the EWF dropped in the vicinity of GB's and the mean EWF decreased as the grain size decreased. The mechanism responsible for the changes in the EWF with respect to the GB is discussed.


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