Layer-by-layer and step-flow growth mechanisms in GaAsP/GaP nanowire heterostructures

2006 ◽  
Vol 21 (11) ◽  
pp. 2801-2809 ◽  
Author(s):  
C. Chen ◽  
M.C. Plante ◽  
C. Fradin ◽  
R.R. LaPierre
Keyword(s):  
Molecular Beam ◽  
Stacking Faults ◽  
Layer Growth ◽  
Growth Mode ◽  
Layer By Layer ◽  
Step Flow ◽  
Gas Source ◽  
Constant Diameter ◽  
Step Flow Growth ◽  
Tapered Region

GaP–GaAsP segmented nanowires (NWs), with diameters ranging between 20 and 500 nm and lengths between 0.5 and 2 μm, were catalytically grown from Au particles on a GaAs (111)B substrate in a gas source molecular beam epitaxy system. The morphology of the NWs was either pencil-shaped with a tapered tip or rod-shaped with a constant diameter along the entire length. Stacking faults were observed for most NWs with diameters greater than 30 nm, but thinner ones tended to exhibit fewer defects. Moreover, stacking faults were more likely found in GaAsP than in GaP. The composition of the pencil NWs exhibited a core–shell structure at the interface region, and rod-shaped NWs resulted in planar and atomically abrupt heterointerfaces. A detailed growth mechanism is presented based on a layer-by-layer growth mode for the rod-shaped NWs and a step-flow growth mode for the tapered region of the pencil NWs.

Sublimation Growth of 6H-SiC Boule on Various a-Plane Substrates

2000 ◽  
Vol 640 ◽  
Author(s):  
S. Nishino ◽  
T. Nishiguchi ◽  
Y. Masuda ◽  
M. Sasaki ◽  
S. Ohshima
Keyword(s):  
Growth Temperature ◽  
Layer Growth ◽  
Growth Mode ◽  
Layer By Layer ◽  
Step Bunching ◽  
Step Flow ◽  
Cvd Growth ◽  
The Difference ◽  
Step Flow Growth ◽  
Sublimation Growth

ABSTRACTSublimation growth of 6H-SiC was performed on {1100} and {1120} substrates. The difference between the growth on {1100} plane and {1120} plane was observed. {1100} facet was almost flat and there were grooves oriented toward <1120> direction. The step bunching was observed on {1100} plane 5° off-axis. A lot of pits were introduced on {1120} plane of the crystal grown both on {1100} and {1120} substrates. Step flow growth toward <1120> direction created the pits on {1120} plane. It was important to grow crystal by layer by layer growth on {1120} plane. By changing the growth mode from step flow growth to layer by layer growth, pit on the {1120} plane may be reduced as same as CVD growth on {1120} plane. Growth temperature and C/Si ratio should be optimized to keep layer by layer growth.

Epitaxial Solid-Solution Films of Immiscible MgO and CaO

1994 ◽  
Vol 341 ◽  
Author(s):  
E. S. Hellman ◽  
E. H. Hartford
Keyword(s):  
Solid Solution ◽  
Molecular Beam Epitaxy ◽  
Lattice Constant ◽  
Solid Solutions ◽  
Molecular Beam ◽  
Building Blocks ◽  
Layer Growth ◽  
Growth Mode ◽  
Miscibility Gap ◽  
Layer By Layer

AbstractMetastable solid-solutions in the MgO-CaO system grow readily on MgO at 300°C by molecular beam epitaxy. We observe RHEED oscillations indicating a layer-by-layer growth mode; in-plane orientation can be described by the Matthews theory of island rotations. Although some films start to unmix at 500°C, others have been observed to be stable up to 900°C. The Mgl-xCaxO solid solutions grow despite a larger miscibility gap in this system than in any system for which epitaxial solid solutions have been grown. We describe attempts to use these materials as adjustable-lattice constant epitaxial building blocks

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).

Effects of hydrogen in AlAs growth by atomic hydrogenassisted molecular beam epitaxy

1999 ◽  
Vol 570 ◽  
Author(s):  
Kee-Youn Jang ◽  
Yoshitaka Okada ◽  
Mitsuo Kawabe
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
High Energy ◽  
Growth Mode ◽  
Flow Mode ◽  
High Energy Electron ◽  
Step Flow ◽  
Gaas Substrates ◽  
Lower Temperature ◽  
Step Flow Growth

ABSTRACTThe transition temperature Tc for the AlAs growth to change from/to a nucleation mode and step-flow mode have been studied on vicinal GaAs substrates (A-surface and B-surface) in molecular beam epitaxy (MBE) and atomic hydrogen-assisted MBE (H-MBE) using reflection high-energy electron diffraction (RHEED). The lowering of Tc was clearly observed in H-MBE compared to conventional MBE. For growth of AlAs on vicinal GaAs substrate in H-MBE, atomic H is thought to promote not only the re-evaporation of Al adatoms on the terrace, but also the incorporation of Al at the step edges, thereby facilitating a step-flow growth mode at a lower temperature than in MBE. The differences in the fundamental growth mode between on A-surface and B-surface have also been studies based on the differences in the atomic structure between the two substrates.

Initial Stage of Heteroepitaxial Growth of SiC on Si by Gas Source MBE Using Hydrocarbon Radicals

1993 ◽  
Vol 318 ◽  
Author(s):  
Takashi Fuyuki ◽  
Yoichiro Tarui ◽  
Tomoaki Hatayama ◽  
Hiroyuki Matsunami
Keyword(s):  
Molecular Beam ◽  
High Energy ◽  
Layer Growth ◽  
Layer By Layer ◽  
Heteroepitaxial Growth ◽  
Homoepitaxial Growth ◽  
Gas Source ◽  
Initial Stage ◽  
Hydrocarbon Radicals ◽  
Gas Source Mbe

ABSTRACTHeteroepitaxial growth of 3C-SiC on Si in gas source molecular beam epitaxy ( GSMBE ) was carried out by a combination of carbonization of a Si surface and subsequent crystal growth on it using hydrocarbon radicals and Si2H6. The carbonization process and the initial stage of the subsequent growth during the intermittent supply of Si2H6 have been studied by a reflection high-energy electron diffraction (RHEED) observation. A Si surface was chemically converted to 3C-SiC at 750°C, and homoepitaxial growth on the carbonized layer could be obtained at 1000°C. Si atoms generated by thermal decomposition on a surface would react with hydrocarbon radicals, forming SiC through a layer by layer growth mode.

Oblique-incidence Reflectivity Difference (OI-RD) and Leed Studies of Adsorption and Growth of Xe on Nb(110)

2003 ◽  
Vol 780 ◽  
Author(s):  
P. Thomas ◽  
E. Nabighian ◽  
M.C. Bartelt ◽  
C.Y. Fong ◽  
X.D. Zhu
Keyword(s):  
Transition Layer ◽  
Layer Growth ◽  
Flow Mode ◽  
Layer By Layer ◽  
Zeroth Order ◽  
Step Flow ◽  
Low Energy Electron Diffraction ◽  
Oriented Film ◽  
Low Energy Electron

AbstractWe studied adsorption, growth and desorption of Xe on Nb(110) using an in-situ obliqueincidence reflectivity difference (OI-RD) technique and low energy electron diffraction (LEED) from 32 K to 100 K. The results show that Xe grows a (111)-oriented film after a transition layer is formed on Nb(110). The transition layer consists of three layers. The first two layers are disordered with Xe-Xe separation significantly larger than the bulk value. The third monolayer forms a close packed (111) structure on top of the tensile-strained double layer and serves as a template for subsequent homoepitaxy. The adsorption of the first and the second layers are zeroth order with sticking coefficient close to one. Growth of the Xe(111) film on the transition layer proceeds in a step flow mode from 54K to 40K. At 40K, an incomplete layer-by-layer growth is observed while below 35K the growth proceeds in a multilayer mode.

The Dynamical Transition to Step-Flow Growth During Homoepitaxy of GaAs (001)

1993 ◽  
Vol 312 ◽  
Author(s):  
B. G. Orr ◽  
J. Sudijono ◽  
M. D. Johnson
Keyword(s):  
Scanning Tunneling Microscope ◽  
Molecular Beam ◽  
Scanning Tunneling ◽  
Oscillatory Regime ◽  
Step Flow ◽  
Microscope Images ◽  
Step Density ◽  
Step Flow Growth ◽  
Direct Correspondence ◽  
Density Results

AbstractThe evolution of surface morphology of molecular-beam-epitaxy-grown GaAs (001) has been studied by scanning tunneling microscope. Images show that in the early stages of deposition the morphology oscillates between one -with twodimensional nucleation and coalescing islands, i.e. flat terraces. After the initial oscillatory regime, the system evolves to a dynamical steady state. This state is characterized by a constant step density. As such, the growth mode can be called a generalized step flow. Comparison with RHEED shows that there is a direct correspondence between the surface step density and the RHEED specular intensity. An increase in step density results in a decrease in specular intensity. Additionally, further deposition beyond 120 monolayers (up to 1450 monolayers) display a slowly increasing surface roughness.

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.

scholarly journals Step-flow growth of graphene-boron nitride lateral heterostructures by molecular beam epitaxy

2D Materials ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 035014 ◽  
Author(s):  
James Thomas ◽  
Jonathan Bradford ◽  
Tin S Cheng ◽  
Alex Summerfield ◽  
James Wrigley ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Boron Nitride ◽  
Molecular Beam ◽  
Step Flow ◽  
Step Flow Growth

scholarly journals Growth mode transition from layer by layer to step flow during the growth of heteroepitaxial SrRuO3 on (001) SrTiO3

2001 ◽  
Vol 79 (10) ◽  
pp. 1447-1449 ◽  
Author(s):  
J. Choi ◽  
C. B. Eom ◽  
G. Rijnders ◽  
H. Rogalla ◽  
D. H. A. Blank
Keyword(s):  
Growth Mode ◽  
Layer By Layer ◽  
Mode Transition ◽  
Step Flow
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