CORRUGATED SURFACES FORMED ON GaAs (331)A SUBSTRATES: THE TEMPLATE FOR LATERALLY ORDERED InGaAs NANOWIRES

2006 ◽  
Vol 05 (06) ◽  
pp. 757-762
Author(s):  
ZHENHUA MIAO ◽  
ZHENG GONG ◽  
ZHIDAN FANG ◽  
ZHICHUAN NIU
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Beam ◽  
Morphology Evolution ◽  
Mbe Growth ◽  
Atomic Force ◽  
Corrugated Surfaces ◽  
Surface Migration ◽  
Terrace Width ◽  
Low Dimensional ◽  
Reduced Surface

Morphology evolution of high-index (331) A surfaces during molecular beam epitaxy (MBE) growth have been investigated in order to uncover their unique physic properties and fabricate spatially ordered low dimensional nanostructures. Atomic Force Microscope (AFM) measurements have shown that the step height and terrace width of GaAs layers increase monotonically with increasing substrate temperature in conventional MBE. However, this situation is reversed in atomic hydrogen-assisted MBE, indicating that step bunching is partly suppressed. We attribute this to the reduced surface migration length of Ga adatoms with atomic hydrogen. By using the step arrays formed on GaAs (331) A surfaces as the templates, we fabricated laterally ordered InGaAs self-aligned nanowires.

Self-Assembled GaAs Quantum Rings by MBE Droplet Epitaxy

2007 ◽  
Vol 121-123 ◽  
pp. 541-544
Author(s):  
She Song Huang ◽  
Zhi Chuan Niu ◽  
Jian Bai Xia
Keyword(s):  
Molecular Beam ◽  
Single Photon ◽  
Photon Emission ◽  
Molecular Beams ◽  
Semiconductor Nanostructures ◽  
Droplet Epitaxy ◽  
Single Photon Emission ◽  
Quantum Rings ◽  
Atomic Force ◽  
Surface Migration

Fabrication of semiconductor nanostructures such as quantum dots (QDs), quantum rings (QRs) has been considered as the important step for realization of solid state quantum information devices, including QDs single photon emission source, QRs single electron memory unit, etc. To fabricate GaAs quantum rings, we use Molecular Beam Epitaxy (MBE) droplet technique in this report. In this droplet technique, Gallium (Ga) molecular beams are supplied initially without Arsenic (As) ambience, forming droplet-like nano-clusters of Ga atoms on the substrate, then the Arsenic beams are supplied to crystallize the Ga droplets into GaAs crystals. Because the morphologies and dimensions of the GaAs crystal are governed by the interplay between the surface migration of Ga and As adatoms and their crystallization, the shape of the GaAs crystals can be modified into rings, and the size and density can be controlled by varying the growth temperatures and As/Ga flux beam equivalent pressures(BEPs). It has been shown by Atomic force microscope (AFM) measurements that GaAs single rings, concentric double rings and coupled double rings are grown successfully at typical growth temperatures of 200°C to 300°C under As flux (BEP) of about 1.0×10-6 Torr. The diameter of GaAs rings is about 30-50 nm and thickness several nm.

Modification of InN Properties by Interactions with Hydrogen and Nitrogen

2005 ◽  
Vol 892 ◽  
Author(s):  
Maria Losurdo ◽  
Maria Michela Giangregorio ◽  
Giovanni Bruno ◽  
Tong-Ho Kim ◽  
Pae Wu ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Beam ◽  
Morphological Changes ◽  
Epitaxial Films ◽  
Intensity Increase ◽  
Force Microscopy ◽  
Atomic Force ◽  
Peak Energy ◽  
Hall Effect Measurements ◽  
The Impact

AbstractThe interaction of InN epitaxial films grown by r.f. plasma assisted molecular beam epitaxy with atomic hydrogen and nitrogen, produced by remote r.f. H2 and N2 plasmas, is investigated. InN strongly reacts with both atomic hydrogen and nitrogen yielding depletion of nitrogen and concurrent formation of In clusters. The impact of hydrogen treatments on the optical properties of InN is assessed using photoluminescence (PL). It is found that hydrogen suppresses the intense PL band peaked at approximately 0.7eV for the as-grown InN epitaxial layers, and results in the appearance of a new PL band whose peak energy and intensity increase with H-dose. The effect of exposure to atomic hydrogen and nitrogen on electrical properties of InN is investigated using Hall effect measurements. Atomic force microscopy is also used for studying the morphological changes of InN upon interaction with atomic hydrogen and nitrogen.

Erbium Doped Gallium Arsenide a Self-Organising Low Dimensional System

1993 ◽  
Vol 301 ◽  
Author(s):  
A.R. Peaker ◽  
H. Efeoglu ◽  
J.M. Langer ◽  
A.C. Wright ◽  
I. Poole ◽  
...  
Keyword(s):  
Gallium Arsenide ◽  
Solubility Limit ◽  
Growth Conditions ◽  
Dimensional System ◽  
Mbe Growth ◽  
Erbium Arsenide ◽  
Surface Migration ◽  
Erbium Doped ◽  
Dot Density ◽  
Low Dimensional

ABSTRACTThe growth of erbium doped gallium arsenide by MBE at normal substrate temperatures (∼580°C) is constrained by a solubility limit of 8×1017 cm−3. This is much less than is desirable for optical emitters using the forbidden 4f transitions of Er3+ to produce radiation at 1.54μm. We have developed an MBE technique where it is possible to produce spherical mesoscopic precipitates containing erbium as a matrix element within the gallium arsenide. Structural and analytical studies indicate that the precipitate is cubic (rock salt) erbium arsenide. The physical size of the precipitates is self limiting as a result of surface migration occurring during MBE growth. By adjusting the growth conditions it is possible to produce an array of uniform erbium arsenide quantum dots of a size chosen from the range 10-20Å. The dot density can be varied by changing the erbium flux.

MBE Growth of IV-VI Nanowires on a Self-organized Template

2010 ◽  
Vol 1258 ◽  
Author(s):  
Lee Andrew Elizondo ◽  
Patrick McCann ◽  
Joel Keay ◽  
Matthew Johnson
Keyword(s):  
Quantum Wires ◽  
High Energy ◽  
Ex Situ ◽  
Mbe Growth ◽  
One Dimensional ◽  
Force Microscopy ◽  
Self Organized ◽  
Atomic Force ◽  
Low Dimensional

AbstractWe present the experimental results for the first known molecular beam epitaxy (MBE) growth of quasi-one-dimensional PbSe wires on technologically relevant silicon.In this work, we describe the growth and characterization of low-dimensional IV-VI semiconductors as they evolve from one-dimensional dot/dot-chains to one-dimensional structures on a self-organized template epitaxially grown on Si(110). In situ and ex situ characterization were performed at various stages throughout growth by reflection high energy electron diffraction, scanning electron microscopy, and non-contact atomic force microscopy. Initial growths resulted in some preferential alignment of the PbSe dot-chains parallel to the self-organized template in the [-110] direction. By reducing the substrate temperature and increasing the supplemental Se flux, the morphology of dot-chains extend into lengthened one-dimensional structures. This is an important milestone in the fabrication of PbSe quantum wires on technologically relevant silicon.

Growth and Properties of Silicon Nanowires for Low-Dimensional Devices

2007 ◽  
Vol 131-133 ◽  
pp. 535-540 ◽  
Author(s):  
P. Werner
Keyword(s):  
Silicon Nanowires ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Semiconductor Nanowires ◽  
Wetting Layer ◽  
Mbe Growth ◽  
Active Point ◽  
Vapor Liquid Solid Mechanism ◽  
Vls Growth ◽  
Low Dimensional

The generation of semiconductor nanowires (NWs) by a “bottom-up” approach is of technological interest for the development of new nanodevices. In most cases Si and SiGe nanowires (NWs) are grown by molecular beam epitaxy (MBE) and by chemical vapor deposition (CVD) on the base of the vapor-liquid-solid-mechanism (VLS). In both cases small metal droplets act as a seed for the NW formation. The article mainly refers to the specific features of the MBE growth. The application of metals related to the VLS growth concept (quite often gold droplets are used) also causes several disadvantages of this approach, e.g., the formation of a metal wetting layer on all surfaces, dislocations, and electric active point defects. Concerning the formation of devices, technological steps, such as oxidation and doping of NWs, have to be considered. Specific techniques have to be applied to investigate the properties of individual semiconductor NWs. Some examples shall illustrate this topic.

GaN layers re-grown on etched GaN templates by plasma assisted molecular beam epitaxy

2003 ◽  
Vol 798 ◽  
Author(s):  
L. He ◽  
J. Xie ◽  
F. Yun ◽  
A. A. Baski ◽  
H. Morkoç
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Extended Defects ◽  
Mbe Growth ◽  
Force Microscopy ◽  
Atomic Force ◽  
Large Lattice ◽  
Defective Region ◽  
Good Template

ABSTRACTThe growth of high-quality GaN by plasma assisted molecular beam epitaxy (MBE) is challenging, in part due to the constraint of heteroepitaxy since GaN substrates are not yet commercially available and isotropic nature of growth. Despite the large lattice and thermal mismatch between sapphire and GaN, the former is still the most commonly used substrate for the GaN-based optical devices at present. In this paper, we demonstrate a re-growth technique to obtain an improved quality GaN by MBE on GaN template on sapphire where the grossly defective regions have been removed. This GaN template is formed by MBE growth of GaN followed by wet chemical etching to selectively remove the defective region. Improved quality GaN was re-grown on such a template under Ga rich conditions to a thickness of about 1 micron. After re-growth, the surface of GaN is atomically smooth with spiral features in the short range. The low temperature PL of the re-grown GaN is superior to those of MBE GaN films directly on sapphire. Atomic force microscopy (AFM) images reveal a two-dimensional re-growth initiating in regions free of extended defects. The results show that the selectively etched GaN on sapphire can be used as a good template to improve the quality of GaN.

GaAs-on-Ge Heteroepitaxy by Atomic Hydrogen-Assisted Molecular Beam Epitaxy (H-MBE)

1995 ◽  
Vol 399 ◽  
Author(s):  
Yoshitaka Okada ◽  
James S. Harris ◽  
Atsushi Sutoh ◽  
Mitsuo Kawabe
Keyword(s):  
Molecular Beam Epitaxy ◽  
Atomic Hydrogen ◽  
Molecular Beam ◽  
High Energy ◽  
Atomic Scale ◽  
Layer By Layer ◽  
High Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Growth System

ABSTRACTThe purpose of this work is to achieve a high-quality epitaxy of GaAs-on-Ge system at low growth temperatures of 300 ∼ 400°C, by atomic hydrogen-assisted molecular beam epitaxy (H-MBE), in attempt to reduce Ge segregation to a minimum and to realize a layer-by-layer two-dimensional (2D) growth mode from the initial stages of the growth. A high-quality heteroepitaxy is expected in H-MBE technique as atomic H is known to act as an effective surfactant modifying the kinetics and energetics of the growth, which are practically difficult to control on atomic-scale unless a third element like a surfactant is introduced into the growth system. It is shown with the support of reflection high-energy electron diffraction (RHEED), secondary ion mass spectroscopy (SIMS), and atomic force microscopy (AFM) characterization that an enhanced layer-by-layer 2D growth can actually be realized and (2×4) GaAs(001) surface can be achieved in low-temperature heteroepitaxy on vicinal Ge(001) substrates at 400 °C by H-MBE.

Nanopatterning of GaAs(110) vicinal surfaces by hydrogen-assisted MBE

2004 ◽  
Vol 849 ◽  
Author(s):  
M. L. Crespillo ◽  
J. L. Sacedón ◽  
B. A. Joyce ◽  
P. Tejedor
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Beam ◽  
Self Organization ◽  
Atomic Step ◽  
Vicinal Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ridge Pattern ◽  
Oxide Removal ◽  
Mound Morphology

ABSTRACTThe effect of atomic hydrogen on the growth mode and surface morphology of GaAs(110) thin films grown by molecular beam epitaxy (H-MBE) has been studied for different kinetic regimes using atomic force microscopy (AFM). Growth in the Ga supply-limited regime after H-assisted oxide removal leads to the formation of multi-atomic step arrays by step bunching with a very uniform terrace size distribution in the 80 nm range. Growth under As-deficient conditions after H-assisted oxide removal induces a rapid self-organization of the GaAs(110) surface into a ridge pattern along the <001> tilt direction, which is broken down into a 3D mound morphology when H is also present during growth. A chacteristic nanofacetting of the surface with very straight <1–10> -type steps is observed at high temperatures regardless of atomic hydrogen being used during oxide desorption and/or epitaxial growth.

Growth of Epitaxial IrSi3 Layers on Si(111)

1989 ◽  
Vol 160 ◽  
Author(s):  
T. L. Lin ◽  
C. W. Nieh
Keyword(s):  
Surface Morphology ◽  
Molecular Beam ◽  
Solid Phase ◽  
Single Mode ◽  
Growth Conditions ◽  
Tem Analysis ◽  
Mbe Growth ◽  
Good Surface ◽  
Transmission Electron

AbstractEpitaxial IrSi3 films have been grown on Si (111) by molecular beam epitaxy (MBE) at temperatures ranging from 630 to 800 °C and by solid phase epitaxy (SPE) at 500 °C. Good surface morphology was observed for IrSi3 layers grown by MBE at temperatures below 680 °C, and an increasing tendency to form islands is noted in samples grown at higher temperatures. Transmission electron microscopy (TEM) analysis reveals that the IrSi3 layers grow epitaxially on Si(111) with three epitaxial modes depending on the growth conditions. For IrSi3 layers grown by MBE at 630 °C, two epitaxial modes were observed with ~ 50% area coverage for each mode. Single mode epitaxial growth was achieved at a higher MBE growth temperature, but with island formation in the IrSi3 layer. A template technique was used with MBE to improve the IrSi3 surface morphology at higher growth temperatures. Furthermore, single-crystal IrSi3 was grown on Si(111) at 500 °C by SPE, with annealing performed in-situ in a TEM chamber.

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