A Surface Diffusion Model for Nanotube Growth

1999 ◽  
Vol 593 ◽  
Author(s):  
Oleg A. Louchev ◽  
Yoichiro Sato
Keyword(s):  
Diffusion Equation ◽  
Surface Diffusion ◽  
Growth Kinetics ◽  
Second Phase ◽  
Island Nucleation ◽  
Step Flow ◽  
Segregation Effect ◽  
Nanotube Growth ◽  
Step Flow Growth ◽  
The Continuum

ABSTRACTThe problem of nanotube growth macrokinetics is viewed within the framework of the continuum surface diffusion equation combined with step-flow growth kinetics. The differences in incorporation rates of adatoms approaching the growth steps from “upper” or lower" terraces are taken into account. These differences can lead to the onset of surface island nucleation in front of a propagating step. This effect is able to cause formation of defects in the growing layer and even to inhibit stable step-flow modes of nanotube growth. The segregation effect of a second phase (BN) in front of the propagating of C layer step is considered, suggesting that it may cause increase in BN concentration and nucleation of islands leading to BN inclusions in C layers or the propagation of a BN layer over C layer.

THE TRANSITION TO STEP FLOW GROWTH ON THE CLEAN AND SURFACTANT COVERED Si(111) SURFACE STUDIED BY IN-SITU LEEM

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4353-4362 ◽  
Author(s):  
W. F. CHUNG ◽  
K. BROMANN ◽  
M. S. ALTMAN
Keyword(s):  
Abrupt Change ◽  
Low Energy ◽  
Clean Surface ◽  
Nucleation Behavior ◽  
Island Nucleation ◽  
Step Flow ◽  
Terrace Width ◽  
Low Energy Electron ◽  
Step Flow Growth

The transition to step flow growth on the clean Si(111) (7×7), Si(111)-In [Formula: see text] and Si(111)-Sb (7×7) surfaces have been investigated using low energy electron microscopy (LEEM). The critical terrace width for step flow on the clean surface displays in Arrhenius behaviour, although with markedly different prefactor and activation energy above and below 750°K. The abrupt change in Arrhenius parameters was revealed by LEEM to correlate with the crossover from homogeneous to heterogeneous island nucleation behavior. The dependence of the critical terrace width upon step orientation is attributed to anisotropic step attachment kinetics. Sb and In surfactants were found to suppress and enhance step flow, respectively, in accordance with expectations. The preparations of Si(111)-Sb (7×7) and Si(111)-In [Formula: see text] surfaces that are morphologically suitable for step flow growth are also described.

scholarly journals Temperature-Dependent Photoluminescence of ZnO Thin Films Grown on Off-Axis SiC Substrates by APMOCVD

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1035
Author(s):  
Ivan Shtepliuk ◽  
Volodymyr Khranovskyy ◽  
Arsenii Ievtushenko ◽  
Rositsa Yakimova
Keyword(s):  
Optical Properties ◽  
Structural Quality ◽  
Organic Chemical ◽  
Zno Films ◽  
Vicinal Surfaces ◽  
Temperature Dependent ◽  
Step Flow ◽  
Step Flow Growth ◽  
First Time ◽  
Temperature Dependent Photoluminescence

The growth of high-quality ZnO layers with optical properties congruent to those of bulk ZnO is still a great challenge. Here, for the first time, we systematically study the morphology and optical properties of ZnO layers grown on SiC substrates with off-cut angles ranging from 0° to 8° by using the atmospheric pressure meta–organic chemical vapor deposition (APMOCVD) technique. Morphology analysis revealed that the formation of the ZnO films on vicinal surfaces with small off-axis angles (1.4°–3.5°) follows the mixed growth mode: from one side, ZnO nucleation still occurs on wide (0001) terraces, but from another side, step-flow growth becomes more apparent with the off-cut angle increasing. We show for the first time that the off-cut angle of 8° provides conditions for step-flow growth of ZnO, resulting in highly improved growth morphology, respectively structural quality. Temperature-dependent photoluminescence (PL) measurements showed a strong dependence of the excitonic emission on the off-cut angle. The dependences of peak parameters for bound exciton and free exciton emissions on temperature were analyzed. The present results provide a correlation between the structural and optical properties of ZnO on vicinal surfaces and can be utilized for controllable ZnO heteroepitaxy on SiC toward device-quality ZnO epitaxial layers with potential applications in nano-optoelectronics.

Growth of (Zn)CdSe quantum structures on vicinal GaAs(001) substrates: step flow growth versus strain effects

2000 ◽  
Vol 214-215 ◽  
pp. 606-609 ◽  
Author(s):  
T Passow ◽  
H Heinke ◽  
D Kayser ◽  
K Leonardi ◽  
D Hommel
Keyword(s):  
Quantum Structures ◽  
Strain Effects ◽  
Step Flow ◽  
Step Flow Growth ◽  
Versus Strain

Development of Cross-Hatch Morphology During Growth of Lattice Mismatched Layers

2001 ◽  
Vol 673 ◽  
Author(s):  
A. Maxwell Andrews ◽  
J.S. Speck ◽  
A.E. Romanov ◽  
M. Bobeth ◽  
W. Pompe
Keyword(s):  
Misfit Dislocation ◽  
Film Growth ◽  
Strain Relaxation ◽  
Dislocation Generation ◽  
Force Microscopy ◽  
Step Flow ◽  
Atomic Force ◽  
Subsequent Step ◽  
Step Flow Growth ◽  
Lateral Scale

ABSTRACTAn approach is developed for understanding the cross-hatch morphology in lattice mismatched heteroepitaxial film growth. It is demonstrated that both strain relaxation associated with misfit dislocation formation and subsequent step elimination (e.g. by step-flow growth) are responsible for the appearance of nanoscopic surface height undulations (0.1-10 nm) on a mesoscopic (∼100 nm) lateral scale. The results of Monte Carlo simulations for dislocation- assisted strain relaxation and subsequent film growth predict the development of cross-hatch patterns with a characteristic surface undulation magnitude ∼50 Å in an approximately 70% strain relaxed In0.25Ga0.75As layers. The model is supported by atomic force microscopy (AFM) observations of cross-hatch morphology in the same composition samples grown well beyond the critical thickness for misfit dislocation generation.

Nanotube self-organization: Formation by step-flow growth

1999 ◽  
Vol 74 (2) ◽  
pp. 194-196 ◽  
Author(s):  
Oleg A. Louchev ◽  
Yoichiro Sato
Keyword(s):  
Self Organization ◽  
Step Flow ◽  
Step Flow Growth

Step‐flow growth on strained surfaces

1993 ◽  
Vol 63 (17) ◽  
pp. 2348-2350 ◽  
Author(s):  
C. Ratsch ◽  
A. Zangwill
Keyword(s):  
Step Flow ◽  
Step Flow Growth

Step-flow growth of perovskite PbTiO 3 thin films epitaxially grown on a miscut SrTiO 3 substrate

1998 ◽  
Author(s):  
Kiyotaka Wasa ◽  
Yoko Haneda ◽  
Toshifumi Sato ◽  
Hideaki Adachi ◽  
Isaku Kanno ◽  
...  
Keyword(s):  
Thin Films ◽  
Step Flow ◽  
Step Flow Growth
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