Frank-van der Merwe Growth in Bilayer Graphene

2020 ◽  
Author(s):  
Haozhe Wang ◽  
Zhenpeng Yao ◽  
Wei Sun Leong ◽  
Gang Seob Jung ◽  
Qichen Song ◽  
...  
Keyword(s):  
Bilayer Graphene ◽  
Growth Mode ◽  
Monolayer Graphene ◽  
Layer By Layer ◽  
Large Area ◽  
Island Growth ◽  
Free Standing ◽  
Adhesive Energy ◽  
Twisting Angle

<p>Bilayer graphene has attracted interest for its unique properties, including interesting electrical behavior when one layer is slightly rotated relative to the other. However, the quality of large-area bilayer graphene is often limited by the layer-plus-island growth mode in which islands of thicker graphene present as unavoidable impurities. Here, we report the observation of the layer-by-layer, Frank-van der Merwe (FM) growth mode in bilayer graphene where multilayer impurities are suppressed. Instead of the conventional surface adhesive energy, it is found that interface adhesive energy is possible to be tuned with an oxidative pretreatment. The FM-grown bilayer graphene is of AB-stacking or with small-twisting-angle (θ = 0-5°), which is more mechanically robust compared to monolayer graphene, facilitating a free-standing wet transfer technology.</p>

Frank-van der Merwe Growth in Bilayer Graphene

2020 ◽  
Author(s):  
Haozhe Wang ◽  
Zhenpeng Yao ◽  
Wei Sun Leong ◽  
Gang Seob Jung ◽  
Qichen Song ◽  
...  
Keyword(s):  
Bilayer Graphene ◽  
Growth Mode ◽  
Monolayer Graphene ◽  
Layer By Layer ◽  
Large Area ◽  
Island Growth ◽  
Free Standing ◽  
Adhesive Energy ◽  
Twisting Angle

<p>Bilayer graphene has attracted interest for its unique properties, including interesting electrical behavior when one layer is slightly rotated relative to the other. However, the quality of large-area bilayer graphene is often limited by the layer-plus-island growth mode in which islands of thicker graphene present as unavoidable impurities. Here, we report the observation of the layer-by-layer, Frank-van der Merwe (FM) growth mode in bilayer graphene where multilayer impurities are suppressed. Instead of the conventional surface adhesive energy, it is found that interface adhesive energy is possible to be tuned with an oxidative pretreatment. The FM-grown bilayer graphene is of AB-stacking or with small-twisting-angle (θ = 0-5°), which is more mechanically robust compared to monolayer graphene, facilitating a free-standing wet transfer technology.</p>

scholarly journals Initial Growth and Crystallization Onset of Plasma Enhanced-Atomic Layer Deposited ZnO

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 291
Author(s):  
Alberto Perrotta ◽  
Julian Pilz ◽  
Roland Resel ◽  
Oliver Werzer ◽  
Anna Maria Coclite
Keyword(s):  
Atomic Layer ◽  
Layer Growth ◽  
Growth Mode ◽  
Ex Situ ◽  
Native Oxide ◽  
Layer By Layer ◽  
Initial Growth ◽  
Island Growth ◽  
X Ray ◽  
Crystallization Onset

Direct plasma enhanced-atomic layer deposition (PE-ALD) is adopted for the growth of ZnO on c-Si with native oxide at room temperature. The initial stages of growth both in terms of thickness evolution and crystallization onset are followed ex-situ by a combination of spectroscopic ellipsometry and X-ray based techniques (diffraction, reflectivity, and fluorescence). Differently from the growth mode usually reported for thermal ALD ZnO (i.e., substrate-inhibited island growth), the effect of plasma surface activation resulted in a substrate-enhanced island growth. A transient region of accelerated island formation was found within the first 2 nm of deposition, resulting in the growth of amorphous ZnO as witnessed with grazing incidence X-ray diffraction. After the islands coalesced and a continuous layer formed, the first crystallites were found to grow, starting the layer-by-layer growth mode. High-temperature ALD ZnO layers were also investigated in terms of crystallization onset, showing that layers are amorphous up to a thickness of 3 nm, irrespective of the deposition temperature and growth orientation.

Oxygen Pressure Dependence of Morphology of Morphology of La2-xSrxCuO4 Ultra-Thin Films

1997 ◽  
Vol 11 (21n22) ◽  
pp. 981-987
Author(s):  
H. Q. Yin ◽  
T. Arakawa ◽  
Y. Kaneda ◽  
T. Yoshikawa ◽  
N. Haneji ◽  
...  
Keyword(s):  
Thin Films ◽  
Pressure Dependence ◽  
Film Growth ◽  
Ambient Pressure ◽  
High Energy ◽  
Layer Growth ◽  
Growth Mode ◽  
Layer By Layer ◽  
Island Growth ◽  
Experimental Conditions

La 2-x Sr x CuO 4 ultra-thin films with thickness 200 Å were fabricated by pulsed laser deposition method in oxygen ( O 2) atmosphere. The morphology of deposited films was investigated by reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM) and scanning electronic microscopy (SEM). The strong oxygen ambient pressure dependence of film morphology was observed. In high oxygen ambient pressure, the film growth is dominated by island growth mode. The results imply that the experimental conditions of oxygen ambient pressure and substrate temperature are critical for the layer-by-layer growth mode.

Polishing of Free-Standing CVD Diamond Films by the Combination of EDM and CMP

2008 ◽  
Vol 53-54 ◽  
pp. 111-118
Author(s):  
Ze Wei Yuan ◽  
Zhu Ji Jin ◽  
B.X. Dong ◽  
Ren Ke Kang
Keyword(s):  
Diamond Film ◽  
High Efficiency ◽  
Cvd Diamond ◽  
Large Area ◽  
Free Standing ◽  
Electro Discharge Machining ◽  
Diamond Polishing ◽  
Before And After ◽  
Cvd Diamond Film

Although various diamond polishing techniques have been studied for many years, no individual method can polish free-standing CVD diamond film with high efficiency and high polishing quality. This paper investigates polishing CVD diamond film by the combination of electro-discharge machining (EDM) and chemical mechanical polishing (CMP). Scanning electro microscopy, Optical microscopy, Energy dispersive X-ray analysis, Talysurf surface profiler and Raman spectroscopy were used to evaluate the surface integrity and quality of diamond film before and after polishing. Based on the experimental results, the material removal during EDM process can be a chemo-mechanical process, including gasification, melting, sputtering, oxidation and graphitization. While in CMP process, diamond was removed under the mechanical and tribochemical interaction. The combination of EDM and CMP has advantages of high efficiency, high polishing quality and low damage. It is suitable to polish large area free-standing CVD diamond film.

Large Area Quasi-Free Standing Monolayer Graphene on 3C-SiC(111)

2012 ◽  
Vol 717-720 ◽  
pp. 617-620 ◽  
Author(s):  
Ulrich Starke ◽  
Camilla Coletti ◽  
Konstantin Emtsev ◽  
Alexei A. Zakharov ◽  
Thierry Ouisse ◽  
...  
Keyword(s):  
Graphene Layer ◽  
Large Scale ◽  
Bulk Crystal ◽  
Monolayer Graphene ◽  
Graphene Monolayer ◽  
Large Area ◽  
Free Standing ◽  
Hydrogen Intercalation

Large scale, homogeneous quasi-free standing monolayer graphene is obtained on a (111) oriented cubic SiC bulk crystal. The free standing monolayer was prepared on the 3C-SiC(111) surface by hydrogen intercalation of a -reconstructed carbon monolayer, so-called zerolayer graphene, which had been grown in Ar atmosphere. The regular morphology of the surface, the complete chemical and structural decoupling of the graphene layer from the SiC substrate as well as the development of sharp monolayer p-bands are demonstrated. On the resulting sample, homogeneous graphene monolayer domains extend over areas of hundreds of square-micrometers.

Either step-flow or layer-by-layer growth for AlN on SiC (0001) substrates

2003 ◽  
Vol 798 ◽  
Author(s):  
Jun Suda ◽  
Norio Onojima ◽  
Tsunenobu Kimoto ◽  
Hiroyuki Matsunami
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
High Growth ◽  
Layer Growth ◽  
Growth Mode ◽  
Crystalline Quality ◽  
Layer By Layer ◽  
Surface Pretreatment ◽  
Step Flow

ABSTRACTAlN was grown on 4H- or 6H-SiC (0001) on-axis substrates by plasma-assisted molecular beam epitaxy. By utilizing optimized SiC surface pretreatment, RHEED oscillations just after the growth of AlN were obtained with high reproducibility. This study focused on the growth kinetics of AlN and the correlation between kinetics and the crystalline quality of the grown layers. It was found that the growth mode changed from layer-by-layer to step-flow for high growth temperatures, while for lower temperatures the layer-by-layer growth mode persisted. The mechanism responsible for the change in growth mode is discussed. Symmetrical (0002) and asymmetrical (01–14) x-ray rocking curve measurements were carried out to evaluate the crystalline quality. For the (0002) peak, both high-temperature and low-temperature grown layers showed almost the same FWHM values. On the other hand, for the (01–14) peak, the FWHM of low-temperature grown AlN was much smaller (180 arcsec) than that of the high-temperature grown AlN (450 arcsec).

scholarly journals Homogeneous Large-Area Quasi-Free-Standing Monolayer and Bilayer Graphene on SiC

2019 ◽  
Vol 2 (2) ◽  
pp. 844-852 ◽  
Author(s):  
D. Momeni Pakdehi ◽  
K. Pierz ◽  
S. Wundrack ◽  
J. Aprojanz ◽  
T. T. N. Nguyen ◽  
...  
Keyword(s):  
Bilayer Graphene ◽  
Large Area ◽  
Free Standing

Free standing GaN nano membrane by laser lift-off method

2012 ◽  
Vol 1432 ◽  
Author(s):  
Liang Tang ◽  
Yuefeng Wang ◽  
Gary Cheng ◽  
Michael J. Manfra ◽  
Timothy D. Sands
Keyword(s):  
Defect Density ◽  
Sacrificial Layer ◽  
Pulsed Laser ◽  
Large Area ◽  
Free Standing ◽  
Sapphire Substrates ◽  
Device Applications ◽  
Lift Off ◽  
Gan Film

ABSTRACTIn this work, we present a method able to fabricate thin GaN nanomembranes fit for device applications. Starting from commercial GaN on sapphire substrates, MBE was used to deposit a sacrificial layer, which comprises of a superlattice of InN/InGaN, after which thin a GaN film of hundreds of nanometers thickness was grown on top. Pulsed laser irridiation with photon energy of 2.3eV gives rise to the controlled decomposition of the sacrificial intermediate layer, which can be followed by easy separation of the top GaN membrane from the substrate. This process can be used to manufacture GaN membranes with low defect density and a wider range of thickness. We demonstrated that large area, free-standing GaN membranes, with a thickness from 200nm and up, could be made using this method, and the high crystal quality of the lift-off GaN layers is well preserved in this process.

scholarly journals Large area quasi-free standing monolayer graphene on 3C-SiC(111)

2011 ◽  
Vol 99 (8) ◽  
pp. 081904 ◽  
Author(s):  
C. Coletti ◽  
K. V. Emtsev ◽  
A. A. Zakharov ◽  
T. Ouisse ◽  
D. Chaussende ◽  
...  
Keyword(s):  
Monolayer Graphene ◽  
Large Area ◽  
Free Standing

Segregation and Interdiffusion of in Atoms in GaAs/InAs/GaAs Heterostructures

1993 ◽  
Vol 312 ◽  
Author(s):  
T. Kawai ◽  
H. Yonezu ◽  
Y. Ogasawara ◽  
D. Saito ◽  
K. Pak
Keyword(s):  
Growth Temperature ◽  
Three Dimensional ◽  
Film Surface ◽  
Growth Direction ◽  
Layer Growth ◽  
Growth Mode ◽  
Layer By Layer ◽  
Island Growth ◽  
Alas Layer ◽  
Secondary Ion

AbstractThe segregation and interdiffusion of In atoms in the GaAs/InAs/GaAs heterostructures were investigated by secondary ion mass spectroscopy. When the 1 ML thick InAs layer was grown in a layer-by-layer growth mode with no dislocations, the segregation of In atoms became marked with the increase of the growth temperature. However, the segregation was observed even at relatively low growth temperature of 400°C in molecular beam epitaxy. It was found that the segregation was markedly enhanced by dislocations near the heterointerface when the thick InAs layers were grown in a three-dimensional island growth mode. The interdiffusion of In atoms toward the growth direction occurred after thermal annealing, which could be assisted by vacancies propagating from the film surface into epilayer. It became apparent that the interdiffusion was effectively suppressed by a thin AlAs layer inserted in the GaAs cap layer.

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