scholarly journals Transfer of Graphene with Protective Oxide Layers

2018 ◽  
Vol 2 (4) ◽  
pp. 58 ◽  
Author(s):  
Haim Grebel ◽  
Liliana Stan ◽  
Anirudha Sumant ◽  
Yuzi Liu ◽  
David Gosztola ◽  
...  

Transfer of graphene, grown by chemical vapor deposition (CVD), to a substrate of choice, typically involves the deposition of a polymeric layer (for example, poly(methyl methacrylate) (PMMA), or polydimethylsiloxane, PDMS). These polymers are quite hard to remove without leaving some residues behind. One method to improve the graphene transfer is to coat the graphene with a thin protective oxide layer, followed by the deposition of a very thin polymer layer on top of the oxide layer (much thinner than the usual thickness), followed by a more aggressive polymeric removal method, thus leaving the graphene intact. At the same time, having an oxide layer on graphene may serve applications, such as channeled transistors or sensing devices. Here, we study the transfer of graphene with a protective thin oxide layer grown by atomic layer deposition (ALD). We follow the transfer process from the graphene growth stage through oxide deposition until completion. We report on the nucleation growth process of oxides on graphene, their resultant strain and their optical transmission.

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Hongyan Xu ◽  
Mohammad Karbalaei Akbari ◽  
Serge Zhuiykov

AbstractTwo-dimensional (2D) semiconductors beyond graphene represent the thinnest stable known nanomaterials. Rapid growth of their family and applications during the last decade of the twenty-first century have brought unprecedented opportunities to the advanced nano- and opto-electronic technologies. In this article, we review the latest progress in findings on the developed 2D nanomaterials. Advanced synthesis techniques of these 2D nanomaterials and heterostructures were summarized and their novel applications were discussed. The fabrication techniques include the state-of-the-art developments of the vapor-phase-based deposition methods and novel van der Waals (vdW) exfoliation approaches for fabrication both amorphous and crystalline 2D nanomaterials with a particular focus on the chemical vapor deposition (CVD), atomic layer deposition (ALD) of 2D semiconductors and their heterostructures as well as on vdW exfoliation of 2D surface oxide films of liquid metals.


Coatings ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 5 ◽  
Author(s):  
César Masse de la Huerta ◽  
Viet Nguyen ◽  
Jean-Marc Dedulle ◽  
Daniel Bellet ◽  
Carmen Jiménez ◽  
...  

Within the materials deposition techniques, Spatial Atomic Layer Deposition (SALD) is gaining momentum since it is a high throughput and low-cost alternative to conventional atomic layer deposition (ALD). SALD relies on a physical separation (rather than temporal separation, as is the case in conventional ALD) of gas-diluted reactants over the surface of the substrate by a region containing an inert gas. Thus, fluid dynamics play a role in SALD since precursor intermixing must be avoided in order to have surface-limited reactions leading to ALD growth, as opposed to chemical vapor deposition growth (CVD). Fluid dynamics in SALD mainly depends on the geometry of the reactor and its components. To quantify and understand the parameters that may influence the deposition of films in SALD, the present contribution describes a Computational Fluid Dynamics simulation that was coupled, using Comsol Multiphysics®, with concentration diffusion and temperature-based surface chemical reactions to evaluate how different parameters influence precursor spatial separation. In particular, we have used the simulation of a close-proximity SALD reactor based on an injector manifold head. We show the effect of certain parameters in our system on the efficiency of the gas separation. Our results show that the injector head-substrate distance (also called deposition gap) needs to be carefully adjusted to prevent precursor intermixing and thus CVD growth. We also demonstrate that hindered flow due to a non-efficient evacuation of the flows through the head leads to precursor intermixing. Finally, we show that precursor intermixing can be used to perform area-selective deposition.


2019 ◽  
Vol 10 (1) ◽  
pp. 21-28
Author(s):  
Martyn Pemble ◽  
Ian Povey ◽  
Dimitra Vernardou

A modified, thermal atomic layer deposition process was employed for the pulsed chemical vapor deposition growth of vanadium pentoxide films using tetrakis (dimethylamino) vanadium and water as a co-reagent.Depositions were carried out at 350oC for 400 pulsed CVD cycles, and samples were subsequently annealed for 1hour at 400°C in air to form materials with enhanced cycling stability during the continuous lithium-ion intercala­tion/deintercalation processes. The diffusion coefficient was estimated to be 2.04x10-10 and 4.10x10-10 cm2 s-1 for the cathodic and anodic processes, respectively. These values are comparable or lower than those reported in the literature, indicating the capability of Li+ of getting access into the vanadium pentoxide framework at a fast rate. Overall, it presents a specific discharge capacity of 280 mAh g-1, capacity retention of 75 % after 10000 scans, a coulombic efficiency of 100 % for the first scan, dropping to 85 % for the 10000th scan, and specific energy of 523 Wh g-1.


2006 ◽  
Vol 914 ◽  
Author(s):  
Kenichi Sekimoto ◽  
Taishi Furukawa ◽  
Noriaki Oshima ◽  
Ken-ichi Tada ◽  
Tetsu Yamakawa

AbstractA novel tantalum precursor, bis(ethylcyclopentadienyl)hydridocarbonyltantalum (Ta(EtCp)2(CO)H EtCp:ethylcyclopentadienyl), for chemical vapor deposition (CVD) and atomic layer deposition (ALD) was synthesized. The molecular structure of this precursor was determined by 1H and 13C NMR, IR, ICP-AES and elemental analysis. This precursor is liquid at room temperature, and its vapor pressure and decomposition temperature indicates that this precursor is suitable for CVD and ALD process.The composition analysis of metal tantalum films deposited by thermal CVD revealed that the concentration of carbon was larger than tantalum. On the other hand, an argon plasma CVD technique reduced the carbon concentration drastically.


2020 ◽  
Vol 13 (7) ◽  
pp. 1997-2023 ◽  
Author(s):  
James A. Raiford ◽  
Solomon T. Oyakhire ◽  
Stacey F. Bent

A review on the versatility of atomic layer deposition and chemical vapor deposition for the fabrication of stable and efficient perovskite solar cells.


2020 ◽  
Vol 8 (18) ◽  
pp. 9292-9301
Author(s):  
Ivan A. Moreno-Hernandez ◽  
Sisir Yalamanchili ◽  
Harold J. Fu ◽  
Harry A. Atwater ◽  
Bruce S. Brunschwig ◽  
...  

A protective tin oxide layer formed by atomic-layer deposition limits surface recombination at n-Si surfaces and produces ∼620 mV of photovoltage on planar n-Si photoanodes. The layer conformally coats structures such as Si microcone arrays.


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