Graphene Metrology Using Fluorescence Quenching of Different Fluorescent Dyes

2012 ◽  
Vol 1451 ◽  
pp. 51-56 ◽  
Author(s):  
Hamed Hosseini Bay ◽  
Maziar Ghazinejad ◽  
Miroslav Penchev ◽  
Isaac Ruiz ◽  
Zafer Mutlu ◽  
...  

ABSTRACTThe unique structure and properties of graphene initiated broad fundamental and technological research, and highlighted graphene as a new candidate for various applications such as energy storage, solar cells and electronic devices. Chemical vapor deposition (CVD) has been utilized for industrial large-scale synthesis of graphene. Regardless of the synthesis process, graphene should be transferred to arbitrary substrates for different applications. The transfer processes, introduce defects such as wrinkles and cracks in graphene which compromise the properties and applications. In recent years, fundamental research has been focused on characterization of graphene to develop new techniques for large-scale, high-resolution graphene metrology. Herein, a complementary high throughput metrology technique using fluorescent quenching is further investigated for different fluorescent dyes to characterize CVD synthesized graphene.

2021 ◽  
Author(s):  
Somayeh Asgary ◽  
Amir Hoshang Ramezani ◽  
Zhaleh Ebrahimi Nejad

Abstract WS2 flakes have been grown successfully on SiO2 substrate via chemical vapor (CVD) deposition method by reduction and sulfurization of WO3 using Ar/ H2 gas and sulfur evaporated from solid sulfur powder. The prepared samples were characterized by optical microscopy (OM), atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectra and photoluminescence (PL). Large domain WS2 monolayers are obtained by extending the growth time. The perfect triangular single-crystalline WS2 flakes with an average length of more than 35 µm were achieved. The sharp PL peak (∼1.98 eV) and two distinct Raman peaks (E2g and A1g) with a ∼ 71.5 cm-1 peak split indicating that relatively high quality WS2 crystals with a regular triangle shape can be synthesized. Higher growth time shows larger triangular-shaped of WS2.


1990 ◽  
Vol 202 ◽  
Author(s):  
Tri-Rung Yew ◽  
Rafael Reif Reif

ABSTRACTLow temperature silicon selective epitaxial growth on patterned oxidized wafers is becoming crucial to ultra large scale integration (ULSI) technologies. Low temperature processes can reduce dopant redistribution via solid state diffusion so that a sharp transition region can be obtained. This paper presents material characterization of epitaxial films grown on patterned oxidized wafers by ultralow pressure chemical vapor deposition (ULPCVD) from SiH4/SiF4/H2 (≤ 10 mTorr), in which SiF4 was used to explore its capability for selective epitaxial growth. The deposition temperature is 800°C. The effects of the SiF4 addition to SiH4/H2 are discussed. Defects in epitaxial layers resulting from a high composition of the SiF4 during deposition were characterized. Results of in–situ surface cleaning using a SiF4/H2 plasma are also presented.


2011 ◽  
Vol 1303 ◽  
Author(s):  
Xiaojuan Song ◽  
Brent Wagner ◽  
Zhitao Kang

ABSTRACTLarge-scale graphene sheets were grown on thin nickel film coated Si substrates using a reliable and repeatable thermal Chemical Vapor Deposition (CVD) technique. The graphene films were then transferred onto a SiO2 coated Si wafer to fabricate a 5 mm x 5 mm resistive sensor structure. Raman spectroscopy analysis confirmed the existence of graphene. Preliminary sensing results were demonstrated by the detection of hazardous gases such as NO2 and MMH (mono-methyl hydrazine). Characterization of the device channel resistivity (switching response) was conducted as a function of the analyte type and concentration. The sensor response indicates a charge transfer mechanism between the analytes and graphene.


2020 ◽  
Vol 2 (1) ◽  
pp. 22
Author(s):  
Irnik Dionisiev ◽  
Vera Marinova ◽  
Krastyo Buchkov ◽  
Hristosko Dikov ◽  
Ivalina Avramova ◽  
...  

Platinum diselenide (PtSe2), which belongs to the transition metals dichalcogenide (TMDCs) class of 2D materials, is characterized with a transition from semimetal to semiconductor with a thickness variation from bulk to monolayer and found in versatile applications especially in sensors and mid-infrared detectors. In this study we report the large-scale synthesis of PtSe2 layers by thermally assisted selenization of pre-deposited platinum films in a horizontal quartz-tube Chemical Vapor Deposition (CVD) reactor. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for characterization of the obtained 2D PtSe2. It is observed that the Raman spectra of PtSe2 show strong dependence on the thickness (Pt deposition time). XPS analysis was applied to examine the chemical compositions in order to assess the quality of the synthesized PtSe2 films. All the studied properties reveal great potential to obtain continuous layers with a controlled thickness and composition and further potential for integration in functional heterostructures for future nanoelectronic and optoelectronic devices.


Author(s):  
Simon Thomas

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.


Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.


Author(s):  
Marylyn Bennett-Lilley ◽  
Thomas T.H. Fu ◽  
David D. Yin ◽  
R. Allen Bowling

Chemical Vapor Deposition (CVD) tungsten metallization is used to increase VLSI device performance due to its low resistivity, and improved reliability over other metallization schemes. Because of its conformal nature as a blanket film, CVD-W has been adapted to multiple levels of metal which increases circuit density. It has been used to fabricate 16 MBIT DRAM technology in a manufacturing environment, and is the metallization for 64 MBIT DRAM technology currently under development. In this work, we investigate some sources of contamination. One possible source of contamination is impurities in the feed tungsten hexafluoride (WF6) gas. Another is particle generation from the various reactor components. Another generation source is homogeneous particle generation of particles from the WF6 gas itself. The purpose of this work is to investigate and analyze CVD-W process-generated particles, and establish a particle characterization methodology.


Author(s):  
L. Wan ◽  
R. F. Egerton

INTRODUCTION Recently, a new compound carbon nitride (CNx) has captured the attention of materials scientists, resulting from the prediction of a metastable crystal structure β-C3N4. Calculations showed that the mechanical properties of β-C3N4 are close to those of diamond. Various methods, including high pressure synthesis, ion beam deposition, chemical vapor deposition, plasma enhanced evaporation, and reactive sputtering, have been used in an attempt to make this compound. In this paper, we present the results of electron energy loss spectroscopy (EELS) analysis of composition and bonding structure of CNX films deposited by two different methods.SPECIMEN PREPARATION Specimens were prepared by arc-discharge evaporation and reactive sputtering. The apparatus for evaporation is similar to the traditional setup of vacuum arc-discharge evaporation, but working in a 0.05 torr ambient of nitrogen or ammonia. A bias was applied between the carbon source and the substrate in order to generate more ions and electrons and change their energy. During deposition, this bias causes a secondary discharge between the source and the substrate.


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