scholarly journals Low-Humidity Sensing Properties of Multi-Layered Graphene Grown by Chemical Vapor Deposition

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3174 ◽  
Author(s):  
Filiberto Ricciardella ◽  
Sten Vollebregt ◽  
Tiziana Polichetti ◽  
Pasqualina M. Sarro ◽  
Georg S. Duesberg
Keyword(s):  
Chemical Vapor Deposition ◽  
Relative Humidity ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Morphological Properties ◽  
Humidity Sensing ◽  
Sensing Properties ◽  
Force Microscopy ◽  
Sensing Material ◽  
Low Humidity

Humidity sensing is fundamental in some applications, as humidity can be a strong interferent in the detection of analytes under environmental conditions. Ideally, materials sensitive or insensitive towards humidity are strongly needed for the sensors used in the first or second case, respectively. We present here the sensing properties of multi-layered graphene (MLG) upon exposure to different levels of relative humidity. We synthesize MLG by chemical vapor deposition, as shown by Raman spectroscopy, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Through an MLG-based resistor, we show that MLG is scarcely sensitive to humidity in the range 30%–70%, determining current variations in the range of 0.005%/%relative humidity (RH) well below the variation induced by other analytes. These findings, due to the morphological properties of MLG, suggest that defective MLG is the ideal sensing material to implement in gas sensors operating both at room temperature and humid conditions.

scholarly journals Growth of U-Shaped Graphene Domains on Copper Foil by Chemical Vapor Deposition

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1887
Author(s):  
Ming Pan ◽  
Chen Wang ◽  
Hua-Fei Li ◽  
Ning Xie ◽  
Ping Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Growth Parameters ◽  
Copper Substrate ◽  
Chemical Vapor ◽  
Morphology Evolution ◽  
Force Microscopy ◽  
Smooth Edge ◽  
Transmission Electron

U-shaped graphene domains have been prepared on a copper substrate by chemical vapor deposition (CVD), which can be precisely tuned for the shape of graphene domains by optimizing the growth parameters. The U-shaped graphene is characterized by using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman. These show that the U-shaped graphene has a smooth edge, which is beneficial to the seamless stitching of adjacent graphene domains. We also studied the morphology evolution of graphene by varying the flow rate of hydrogen. These findings are more conducive to the study of morphology evolution, nucleation, and growth of graphene domains on the copper substrate.

Comparison of Aluminum Nitride Nanowire Growth with and without Catalysts via Chemical Vapor Deposition

2011 ◽  
Vol 1324 ◽  
Author(s):  
Kasif Teker ◽  
Joseph A. Oxenham
Keyword(s):  
Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Systematic Investigation ◽  
Efficient Catalyst ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Direct Nitridation ◽  
20 Nm

ABSTRACTThis paper presents a systematic investigation of AlN nanowire synthesis by chemical vapor deposition using Al and NH3 on SiO2/Si substrate and direct nitridation of mixture of Al-Al2O3 by NH3. A wide variety of catalyst materials, in both discrete nanoparticle and thin film forms, have been used (Co, Au, Ni, and Fe). The growth runs have been carried out at temperatures between 800 and 1100oC mainly under H2 as carrier gas. It was found that the most efficient catalyst in terms of nanowire formation yield was 20-nm Ni film. The AlN nanowire diameters are about 20-30 nm, about the same thickness as the Ni-film. Further studies of direct nitridation of mixture of Al-Al2O3 by NH3 have resulted in high density one-dimensional nanostructure networks at 1100oC. It was observed that catalyst-free nanostructures resulted from the direct nitridation were significantly longer than that with catalysts. The analysis of the grown nanowires has been carried out by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and x-ray diffraction.

Optical and morphological properties of SiNx/Si amorphous multilayer structures grown by Plasma Enhanced Chemical Vapor Deposition

2005 ◽  
Vol 2 (10) ◽  
pp. 3698-3701 ◽  
Author(s):  
G. Santana ◽  
O. de Melo ◽  
J. Aguilar-Hernández ◽  
B. M. Monroy ◽  
J. Fandiño ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Morphological Properties ◽  
Multilayer Structures

Atomic Force Microscopy Study of Initial Nucleation in the Deposition OF μc-Si:H

1999 ◽  
Vol 557 ◽  
Author(s):  
P. Brogueira ◽  
V. Chu ◽  
J.P. Conde
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Microscopy Study ◽  
Dark Conductivity ◽  
Rf Plasma ◽  
Hydrogen Treatment ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe initial stages of microcrystalline silicon growth of n+ doped films prepared by rf plasma enhanced chemical vapor deposition (PECVD) and of intrinsic films prepared by hot-wire chemical vapor deposition (HW-CVD) are studied using atomic force microscopy, Raman spectroscopy and parallel dark conductivity measurements. The effect of the use of a plasma hydrogen treatment, of chamber conditioning prior to this treatment, of the type of substrate (glass or c-Si) used and the effects of a seed layer on the film properties are discussed.

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