Growth of SnS van der Waals Epitaxies on Layered Substrates

2013 ◽  
Vol 1493 ◽  
pp. 213-217 ◽  
Author(s):  
S.F. Wang ◽  
W.K. Fong ◽  
W. Wang ◽  
K.K. Leung ◽  
C. Surya
Keyword(s):  
Molecular Beam ◽  
Crystal Size ◽  
Substrate Surface ◽  
Van Der Waals ◽  
Layered Materials ◽  
Substantial Improvement ◽  
High Quality ◽  
Rocking Curve ◽  
Large Lattice ◽  
Unit Layer

ABSTRACTIn this paper we present systematic investigations on the growth of SnS van der Waals epitaxies (vdWEs) on different substrates, including crystalline and layered substrates, by molecular beam epitaxy (MBE). Experimental growth of SnS on conventional 3D substrates, such as GaAs, indicates strong interaction between the SnS layer and the substrate resulting in poor crystallinity in general. Substantial improvement in the film crystallinity can be obtained when the deposition is made on layered substrates, with saturated surface bonds, as observed in SnS films deposited on mica and crystalline substrates with a graphene buffer layer. Crystal size as large as one micron and rocking curve FWHM of 0.118° was observed despite the large lattice mismatches. This represents significant improvement over the reported value of ∼3°. Several symmetric growth orientations are observed for films grown on mica substrates. The results indicate that weak vdW interactions between the saturated bonds of the substrate surface and the SnS unit layer which is an important factor for achieving high quality epitaxy layered materials.

Gallium Nitride Epitaxy on Silicon: Importance of Substrate Preparation

1995 ◽  
Vol 395 ◽  
Author(s):  
G. A. Martin ◽  
B. N. Sverdlov ◽  
A. Botchkarev ◽  
H. Morkoç ◽  
D. J. Smith ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Substrate Surface ◽  
Substrate Preparation ◽  
Rocking Curve ◽  
X Ray ◽  
Surface Steps ◽  
Threading Defects ◽  
Atomically Flat

ABSTRACTHexagonal GaN films grown on non-isomorphic substrates are usually characterized by numerous threading defects which are essentially boundaries between wurtzite GaN domains where the stacking sequences do not align. One origin of these defects is irregularities on the substrate surface such as surface steps. Using Si <111> substrates and a substrate preparation procedure that makes wide atomically flat terraces, we demonstrate that reduction of these irregularities greatly improves the crystalline and luminescent quality of GaN films grown by plasma-enhanced molecular beam epitaxy. X-ray rocking curve width decreases from over 1 degree to less than 20 minutes, while PL halfwidth decreases from over 15 meV to less than 10 meV.

Molecular beam epitaxy growth of high quality p-doped SnS van der Waals epitaxy on a graphene buffer layer

2012 ◽  
Vol 111 (9) ◽  
pp. 093520 ◽  
Author(s):  
W. Wang ◽  
K. K. Leung ◽  
W. K. Fong ◽  
S. F. Wang ◽  
Y. Y. Hui ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Van Der Waals ◽  
Molecular Beam Epitaxy Growth ◽  
High Quality

The Preparation of Crystalline NbSe2/TiSe2 Superlattices from Modulated Elemental Reactants

1995 ◽  
Vol 382 ◽  
Author(s):  
Myungkeun Noh ◽  
James Thiel ◽  
David C. Johnson
Keyword(s):  
Diffraction Data ◽  
Substrate Surface ◽  
Domain Size ◽  
High Angle ◽  
High Quality ◽  
Rocking Curve ◽  
Modulated Elemental Reactants ◽  
Unit Cells ◽  
Controlled Crystallization ◽  
Elemental Reactants

ABSTRACTThree new crystalline NbSe2/TiSe2 superlattice compounds with 43.472±0.005A, 80.66±0.03A and 117.9±0.1Å unit cells in thec direction were prepared through controlled crystallization of Ti/Se/Nb/Se superlattice reactants with different compositional layer thicknesses. Theta-theta and rocking curve data were collected using a theta-theta diffractometer to study the evolution of the initially layered reactants into the crystalline superlattices as a function of temperature. Low angle diffraction data demonstrates that the initial layered reactant contracts in the c-axis direction upon initial annealing and suggests that the interfaces become smoother during this initial interdiffusion. High angle rocking curve diffraction data shows the development of caxis oriented NbSe2fTiSe2 crystal growth perpendicular to the substrate surface. Theta-theta scans show a gradual decrease of the (001) diffraction linewidths of the growing compound as a function of annealing time and temperature indicating an increase in the c-axis domain size. High quality caxis oriented TiSe2/NbSe2 crystalline superlattices result from annealing at the relatively low temperature of 500ºC. The rational synthesis of intergrowth compounds from superlattice reactants as described herein will permit the tailoring of physical properties as a function of compositional layer thicknesses and nativeproperties of the parent compounds.

scholarly journals Making high-quality quantum microwave devices with van der Waals superconductors

2021 ◽  
Author(s):  
Abhinandan Antony ◽  
Martin V. Gustafsson ◽  
Anjaly Rajendran ◽  
Avishai Benyamini ◽  
Guilhem Ribeill ◽  
...  
Keyword(s):  
Quantum Coherence ◽  
Van Der Waals ◽  
Layered Materials ◽  
Low Loss ◽  
High Quality ◽  
Quantum Devices ◽  
2D Layered Materials ◽  
Value Sets ◽  
Microwave Regime ◽  
Quality Factor Q

Abstract Ultra low-loss microwave materials are crucial for enhancing quantum coherence and scalability of superconducting qubits. Van der Waals (vdW) heterostructure is an attractive platform for quantum devices due to the single-crystal structure of the constituent two-dimensional (2D) layered materials and the lack of dangling bonds at their atomically sharp interfaces. However, new fabrication and characterization techniques are required to determine whether these structures can achieve low loss in the microwave regime. Here we report the fabrication of superconducting microwave resonators using NbSe$_2$ that achieve a quality factor $Q > 10^5$. This value sets an upper bound that corresponds to a resistance of $\leq 192 \mu\Omega$ when considering the additional loss introduced by integrating NbSe$_2$ into a standard transmon circuit. This work demonstrates the compatibility of 2D layered materials with high-quality microwave quantum devices.

Surface Control of ZrB2 (0001) Substrate for Molecular-Beam Epitaxy of GaN

2003 ◽  
Vol 798 ◽  
Author(s):  
Jun Suda ◽  
Hiroyasu Yamashita ◽  
Robert Armitage ◽  
Tsunenobu Kimoto ◽  
Hiroyuki Matsunami
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Substrate Surface ◽  
High Vacuum ◽  
Surface Preparation ◽  
High Energy ◽  
Ultra High Vacuum ◽  
High Quality ◽  
Preparation Methods ◽  
Thermal Cleaning

ABSTRACTZirconium diboride (ZrB2) is a promising lattice-matched substrate for GaN-based materials. A key issue to realize high-quality heteroepitaxial growth is preparation of the substrate surface. The ZrB2 surface was studied by x-ray photoemission spectroscopy (XPS) and reflection high-energy electron diffraction (RHEED). XPS results indicated the presence of both ZrO2 and ZrB2 on the as-received substrate surface. Thermal cleaning at 1000°C in ultra-high vacuum, Ar+ ion sputtering, and wet chemical treatments were examined as surface preparation methods. After treatment with HF acid, the O peak intensity was much reduced. The combination of HF treatment and thermal cleaning resulted in sharp and intense RHEED from the ZrB2 surface. GaN grown on the surface by molecular-beam epitaxy exhibited intense photoluminescence, suggesting that this treatment is effective to obtain high-quality GaN on ZrB2 substrates.

X-Ray Diffraction Studies of Low Temperature GaAs

1991 ◽  
Vol 241 ◽  
Author(s):  
G. Kowaljki ◽  
M. Leszcjynski ◽  
A. Kurpiewski ◽  
M. Kaminska ◽  
T. Suski ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Lattice Relaxation ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Large Lattice ◽  
Low Temperature Gaas ◽  
Substrate Temperatures

ABSTRACTGaAs layers grown by molecular beam epitaxy (MBE) at low substrate temperatures (LT GaAs) were studied in a novel purpose designed X-ray experiment. It combines X-ray double crystal rocking curve measurements with some elements usually found in optical setups like light illumination at liquid nitrogen temperatures applied to transfer EL2 type defects into metastable state. Ability to record such transfers with the X-ray experiment as well as large lattice relaxation accompanying this process is presented.

The Synthesis and Superconducting Behavior of Crystalline Superlattices: (TiSe2)m(NbSe2)n

1996 ◽  
Vol 441 ◽  
Author(s):  
Myungkeun Noh ◽  
David C. Johnson
Keyword(s):  
Annealing Temperature ◽  
Substrate Surface ◽  
Domain Size ◽  
Bragg Diffraction ◽  
Conductivity Measurements ◽  
High Quality ◽  
Rocking Curve ◽  
Integral Number ◽  
Controlled Crystallization ◽  
Diffraction Peaks

AbstractA series of kinetically stable, crystalline superlattices containing an integral number of intergrown TiSe2 and NbSe2 layers have been synthesized by controlled crystallization of elementally modulated reactants. Theta-theta and rocking curve data were collected to study the evolution of the initially layered reactants into the crystalline superlattices as a function of temperature. Nucleation of the dichalcogenide structure occurs upon annealing at temperatures above 200°C with the c-axis oriented perpendicular to the substrate surface. The [00l] diffraction linewidths decrease with increased annealing time and temperature suggesting growth of the c-axis domain size. High quality c-axis oriented dichalcogenide crystalline superlattices result from extended annealing at the relatively low annealing temperature of 500°C. The large number of well resolved [00l] Bragg diffraction peaks confirm the well developed crystal structure of the product superlattices in this direction. Four probe electrical conductivity measurements were used to determine the variation of the superconducting critical temperature as a function of the number of TiSe2 and NbSe2 layers in the superlattice.

Effects of substrate quality and annealing on defect structures at GaAs/Si interfaces

1987 ◽  
Vol 45 ◽  
pp. 340-341
Author(s):  
H. L. Tsai ◽  
J. W. Lee
Keyword(s):  
Growth Process ◽  
Molecular Beam ◽  
Substrate Surface ◽  
Lattice Misfit ◽  
Device Fabrication ◽  
Silicon Substrates ◽  
Defect Structures ◽  
Gaas Film ◽  
Substrate Quality ◽  
Gaas On Si

Growth of GaAs on Si using epitaxial techniques has been receiving considerable attention for its potential application in device fabrication. However, because of the 4% lattice misfit between GaAs and Si, defect generation at the GaAs/Si interface and its propagation to the top portion of the GaAs film occur during the growth process. The performance of a device fabricated in the GaAs-on-Si film can be degraded because of the presence of these defects. This paper describes a HREM study of the effects of both the substrate surface quality and postannealing on the defect propagation and elimination.The silicon substrates used for this work were 3-4 degrees off [100] orientation. GaAs was grown on the silicon substrate by molecular beam epitaxy (MBE).

scholarly journals High performance self-powered photodetector based on 1D Te-2D WS2 mixed-dimensional heterostructure

2021 ◽  
Author(s):  
Lixiang Han ◽  
Mengmeng Yang ◽  
Peiting Wen ◽  
Wei Gao ◽  
nengjie huo ◽  
...  
Keyword(s):  
High Performance ◽  
Van Der Waals ◽  
Sharp Interface ◽  
Two Dimensional ◽  
High Quality ◽  
One Dimensional ◽  
Self Powered

One dimensional (1D)-two dimensional (2D) van der Waals (vdWs) mixed-dimensional heterostructures with advantages of atomically sharp interface, high quality and good compatibility have attracted tremendous attention in recent years. The...

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