Effects of Long-Time Current Annealing to the Hysteresis in CVD Graphene on SiO2

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3319-3326 ◽  
Author(s):  
U. Kushan Wijewardena ◽  
Tharanga Nanayakkara ◽  
Rasanga Samaraweera ◽  
Sajith Withanage ◽  
Annika Kriisa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Hole Transport ◽  
Ambient Conditions ◽  
Back Gate ◽  
Graphene Sample ◽  
Before And After ◽  
Long Time ◽  
Current Annealing

ABSTRACTGraphene specimens produced by chemical vapor deposition usually show p-type characteristics and significant hysteresis in ambient conditions. Among many methods, current annealing appears to be a better way of cleaning the sample due to the possibility of in-situ annealing in the measurement setup. However, long-time current annealing could increase defects in the underlying substrate. Studying the hysteresis with different anneal currents in a graphene device is, therefore, a topic of interest. In this experimental work, we investigate electron/hole transport in a graphene sample in the form of a Hall bar device with a back gate, where the graphene was prepared using chemical vapor deposition on copper foils. We study the hysteresis before and after current annealing the sample by cooling down to a temperature of 35 Kfrom room temperature with a back-gate bias in a closed cycle refrigerator.

Comparisons of Gallium Nitride and Indium Nitride Properties after CF4 / Argon Reactive Ion Etching

2002 ◽  
Vol 743 ◽  
Author(s):  
Marie Wintrebert-Fouquet ◽  
K. Scott ◽  
A. Butcher ◽  
Simon K H Lam
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Indium Nitride ◽  
Reactive Ion Etching ◽  
Film Surface ◽  
Chemical Vapor ◽  
Electrical Characteristics ◽  
Ion Etching ◽  
Before And After

ABSTRACTWe present a comparative study of the effects of low power reactive ion etching (RIE) on GaN and InN. This new, highly chemical, dry etching, using CF4 and Ar, has been developed for thin nitride films grown at low temperature in our laboratories. GaN films were grown by remote plasma enhanced-laser induced chemical vapor deposition and InN films were grown by radio-frequency RF reactive sputtering. Commercial GaN samples were also examined. Optical and electrical characteristics of the films are reported before and after removing 100 to 200 nm of the film surface by RIE. We have previously shown that the GaN films, although polycrystalline after growth, may be re-crystallized below the growth temperature. Removal of the surface oxide has been found to be imperative since a polycrystalline residue remains on the surface after re-crystallization.

Hole transport in Mg-doped GaN epilayers grown by metalorganic chemical vapor deposition

2000 ◽  
Vol 76 (9) ◽  
pp. 1149-1151 ◽  
Author(s):  
K. S. Kim ◽  
M. G. Cheong ◽  
C.-H. Hong ◽  
G. M. Yang ◽  
K. Y. Lim ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Hole Transport ◽  
Metalorganic Chemical ◽  
Mg Doped

Microstructure of the MgH2 Synthesized by Hydriding Chemical Vapor Deposition

2006 ◽  
Vol 971 ◽  
Author(s):  
Itoko Saita ◽  
Tomohiro Akiyama
Keyword(s):  
Chemical Vapor Deposition ◽  
Hydrogen Storage ◽  
Vapor Deposition ◽  
Hydrogen Diffusion ◽  
Chemical Vapor ◽  
Hydrogen Desorption ◽  
Plateau Pressure ◽  
Equilibrium Pressure ◽  
Significant Difference ◽  
Before And After

ABSTRACTIt is hardly achieved to prepare highly pure MgH2 by the conventional method of solid-gas reaction between solid magnesium and hydrogen; therefore, we proposed and succeeded to synthesize MgH2 by Hydriding Chemical Vapor Deposition (HCVD). Very interestingly, the HCVDed MgH2 was made of single crystals with fibrous figures; however, further detail of the HCVDed product had not been studied. Therefore the aim of this study was to examine the HCVDed MgH2 in hydrogen storage and to observe the microstructure of the HCVDed MgH2 after the hydrogen desorption and absorption.As the results of Pressure-Composition-Isotherm (PCT) measurement, the HCVDed MgH2 reversibly absorbed and desorbed 7.6 mass% hydrogen, as much as the theoretical maximum hydrogen capacity of magnesium, without any activation treatment. The equilibrium pressure was slightly lower than the reported value. Before and after the PCT measurement, the HCVDed MgH2 did not showed noticeable difference in figure; however, MgHx, which was prepared dehydriding the HCVDed MgH2 in the PCT, showed significant difference in figure: It had zebra stripes in the SEM observation. This observation showed that the hydrogen storage and release went in the radious direction and the hydrogen diffusion was no more rate-limiting. The phase boundaries of Mg and MgH2 involving strain should affected on the plateau pressure in PCT.

Effects of ambient conditions on the quality of graphene synthesized by chemical vapor deposition

Vacuum ◽  
2012 ◽  
Vol 86 (12) ◽  
pp. 1867-1870 ◽  
Author(s):  
F.T. Si ◽  
X.W. Zhang ◽  
X. Liu ◽  
Z.G. Yin ◽  
S.G. Zhang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Ambient Conditions

Remote Plasma Enhanced-Metal Organic Chemical Vapor Deposition of Zirconium Oxide/Silicon Oxide Alloy, (ZrO2)1-(SiO2)1−x (x:≤0.5), Thin Films for Advanced High-K Gate Dielectrics

1999 ◽  
Vol 567 ◽  
Author(s):  
D. Wolfe ◽  
K. Flock ◽  
R. Therrien ◽  
R. Johnson ◽  
B. Rayner ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Silicon Oxide ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Remote Plasma ◽  
Before And After ◽  
Oxidized Zirconium ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

ABSTRACTA remote plasma enhanced-metal organic chemical vapor deposition (RPE-MOCVD) process was developed for the preparation of non-crystalline (ZrO2)x-(SiO2)1−x (x ≤ 0.5) alloys, targeting the compound composition ZrSiO4with k ∼ 12.5. Shifts in Si LVV and Zr LMM AES energies with respect to elemental values showed that the deposited film was a fully-oxidized zirconium/silicon alloy. FTIR results were consistent with AES, and a Zr-O-Si bonding mode was identified in the spectra. The films were amorphous before and after RTA at 900°C for 30 sec, as monitored via RHEED. Optical absorption measurements indicated the onset of band-to-band transitions at an energy of approximately 6 eV. Finally, C-V testing showed that the films were insulating.

Aerosol-assisted chemical vapor deposition of ultra-thin CuOx films as hole transport material for planar perovskite solar cells

2018 ◽  
Vol 11 (02) ◽  
pp. 1850035 ◽  
Author(s):  
Zhixin Zhang ◽  
Shuqun Chen ◽  
Pingping Li ◽  
Hongyi Li ◽  
Junshu Wu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Low Cost ◽  
Perovskite Solar Cells ◽  
Chemical Vapor ◽  
Ambient Air ◽  
Hole Transport ◽  
Hole Transporting ◽  
First Time

This paper reports on the fabrication of CuOx films to be used as hole transporting layer (HTL) in CH3NH3PbI3 perovskite solar cells (PSCs). Ultra-thin CuOx coatings were grown onto FTO substrates for the first time via aerosol-assisted chemical vapor deposition (AACVD) of copper acetylacetonate in methanol. After incorporating into the PSCs prepared at ambient air, a highest power conversion efficiency (PCE) of 8.26% with HTL and of 3.34% without HTL were achieved. Our work represents an important step in the development of low-cost CVD technique for fabricating ultra-thin metal oxide functional layers in thin film photovoltaics.

scholarly journals Anomalous thickness dependence of Curie temperature in air-stable two-dimensional ferromagnetic 1T-CrTe2 grown by chemical vapor deposition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lingjia Meng ◽  
Zhang Zhou ◽  
Mingquan Xu ◽  
Shiqi Yang ◽  
Kunpeng Si ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Curie Temperature ◽  
Vapor Deposition ◽  
Theoretical Calculations ◽  
Chemical Vapor ◽  
Anomalous Hall Effect ◽  
Two Dimensional ◽  
Ambient Conditions ◽  
Chemical Vapor Deposition Growth ◽  
Out Of Plane

AbstractThe discovery of ferromagnetic two-dimensional van der Waals materials has opened up opportunities to explore intriguing physics and to develop innovative spintronic devices. However, controllable synthesis of these 2D ferromagnets and enhancing their stability under ambient conditions remain challenging. Here, we report chemical vapor deposition growth of air-stable 2D metallic 1T-CrTe2 ultrathin crystals with controlled thickness. Their long-range ferromagnetic ordering is confirmed by a robust anomalous Hall effect, which has seldom been observed in other layered 2D materials grown by chemical vapor deposition. With reducing the thickness of 1T-CrTe2 from tens of nanometers to several nanometers, the easy axis changes from in-plane to out-of-plane. Monotonic increase of Curie temperature with the thickness decreasing from ~130.0 to ~7.6 nm is observed. Theoretical calculations indicate that the weakening of the Coulomb screening in the two-dimensional limit plays a crucial role in the change of magnetic properties.

Chemical Vapor Deposition (CVD) of Iridium and Platinum Films and Gas-Phase Chemical Etching of Iridium Thin Films

1998 ◽  
Vol 541 ◽  
Author(s):  
Chongying Xu ◽  
Frank Dimeo ◽  
Thomas H. Baum ◽  
Michael Russell
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Noble Metal ◽  
Vapor Deposition ◽  
Chemical Etching ◽  
Electrode Materials ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Memory Storage ◽  
Ambient Conditions

AbstractChemical vapor deposition (CVD) of noble metal thin-films is increasingly important for future memory storage applications. Integration of ferroelectric perovskites and/or high permittivity oxides requires specialized metal interconnect technologies. Platinum and iridium are two preferred metal electrode materials being explored since they are highly resistant to corrosion and exhibit excellent stability at high temperatures. Further, the formation of stable oxides (IrO2) provides a mechanism for decreased inter-diffusion of oxygen and elemental film constituents, and provides improved reliability in silicon-based devices. CVD provides conformal electrode films that are required to achieve high-densities; high purity films of both platinum and iridium were deposited in this research, using (β-diketonate)Ir(I)L and (MeCp)Me3Pt(IV) as the precursors.Concurrently, chemical etching of these metals is highly desirable for creating patterns of the electrical contacts and for CVD reactor cleaning. To date, etching of noble metal electrodes has relied upon physical sputtering or chemically assisted etching. In this paper, we also report the first chemical etching of iridium films under ambient conditions, such as room temperature.

scholarly journals Showerhead-assisted chemical vapor deposition of CsPbBr3 films for LED applications

2021 ◽  
Author(s):  
S. Sanders ◽  
G. Simkus ◽  
J. Riedel ◽  
A. Ost ◽  
A. Schmitz ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Layer Growth ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Process Conditions ◽  
Light Emitting ◽  
Direct Growth

AbstractCsPbBr3 represents a highly attractive material for perovskite light-emitting diodes (PeLEDs) in the green spectral range. However, the lack of deposition tools for reproducible and scalable growth of perovskite films is one of the major obstacles hindering PeLED commercialization. Here, we employ the highly scalable showerhead-assisted chemical vapor deposition (CVD) method to produce uniform pinhole-free CsPbBr3 films for PeLED application. The precursors CsBr and PbBr2 are evaporated under low vacuum in N2 carrier gas. By adjusting the PbBr2 sublimation temperature, process conditions for CsBr-rich, stoichiometric, and PbBr2-rich CsPbBr3 layer growth have been developed. A substrate temperature of 160 °C enables direct growth of these CsPbBr3 films on a polymeric hole transport layer (HTL), finally yielding PeLEDs with a maximum luminance of 125 cd/m2. Although the device efficiency still lags behind solution-processed counterparts, our approach presents the first demonstration of PeLEDs containing CsPbBr3 films processed in a perovskite showerhead-assisted CVD reactor. Graphic abstract

Sign in / Sign up

Export Citation Format

Share Document