High-quality two-dimensional tellurium flakes grown by high-temperature vapor deposition

2021 ◽  
Author(s):  
Baoquan Huang ◽  
Zehong Lei ◽  
Xuanhao Cao ◽  
Aixiang Wei ◽  
Lili Tao ◽  
...  
Keyword(s):  
High Temperature ◽  
Vapor Deposition ◽  
High Mobility ◽  
Two Dimensional ◽  
Strong Anisotropy ◽  
High Quality ◽  
High Temperature Vapor

The elemental two-dimensional (2D) tellurium (Te) possesses fascinating properties such as high mobility, strong anisotropy and strong infrared response, which show great potential for various applications. However, the fabrication of...

scholarly journals Investigation of the Heteroepitaxial Process Optimization of Ge Layers on Si (001) by RPCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 928
Author(s):  
Yong Du ◽  
Zhenzhen Kong ◽  
Muhammet Toprak ◽  
Guilei Wang ◽  
Yuanhao Miao ◽  
...  
Keyword(s):  
High Temperature ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Crystalline Quality ◽  
Initial Growth ◽  
Two Dimensional ◽  
High Quality ◽  
Reduced Pressure

This work presents the growth of high-quality Ge epilayers on Si (001) substrates using a reduced pressure chemical vapor deposition (RPCVD) chamber. Based on the initial nucleation, a low temperature high temperature (LT-HT) two-step approach, we systematically investigate the nucleation time and surface topography, influence of a LT-Ge buffer layer thickness, a HT-Ge growth temperature, layer thickness, and high temperature thermal treatment on the morphological and crystalline quality of the Ge epilayers. It is also a unique study in the initial growth of Ge epitaxy; the start point of the experiments includes Stranski–Krastanov mode in which the Ge wet layer is initially formed and later the growth is developed to form nuclides. Afterwards, a two-dimensional Ge layer is formed from the coalescing of the nuclides. The evolution of the strain from the beginning stage of the growth up to the full Ge layer has been investigated. Material characterization results show that Ge epilayer with 400 nm LT-Ge buffer layer features at least the root mean square (RMS) value and it’s threading dislocation density (TDD) decreases by a factor of 2. In view of the 400 nm LT-Ge buffer layer, the 1000 nm Ge epilayer with HT-Ge growth temperature of 650 °C showed the best material quality, which is conducive to the merging of the crystals into a connected structure eventually forming a continuous and two-dimensional film. After increasing the thickness of Ge layer from 900 nm to 2000 nm, Ge surface roughness decreased first and then increased slowly (the RMS value for 1400 nm Ge layer was 0.81 nm). Finally, a high-temperature annealing process was carried out and high-quality Ge layer was obtained (TDD=2.78 × 107 cm−2). In addition, room temperature strong photoluminescence (PL) peak intensity and narrow full width at half maximum (11 meV) spectra further confirm the high crystalline quality of the Ge layer manufactured by this optimized process. This work highlights the inducing, increasing, and relaxing of the strain in the Ge buffer and the signature of the defect formation.

scholarly journals The Progress on Low-Cost, High-Quality, High-Temperature Superconducting Tapes Deposited by the Combustion Chemical Vapor Deposition Process

2001 ◽  
Vol 689 ◽  
Author(s):  
Shara S. Shoup ◽  
Marvis K. White ◽  
Steve L. Krebs ◽  
Natalie Darnell ◽  
Adam C. King ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
High Temperature ◽  
Critical Current Density ◽  
Buffer Layer ◽  
Critical Current ◽  
Vapor Deposition ◽  
Low Cost ◽  
Chemical Vapor ◽  
High Critical Current Density ◽  
High Quality

ABSTRACTThe innovative Combustion Chemical Vapor Deposition (CCVD) process is a non-vacuum technique that is being investigated to enable next generation products in several application areas including high-temperature superconductors (HTS). In combination with the Rolling Assisted Biaxially Textured Substrate (RABiTS) technology, the CCVD process has significant promise to provide low-cost, high-quality lengths of YBCO coated conductor. The CCVD technology has been used to deposit both buffer layer coatings as well as YBCO superconducting layers. A buffer layer architecture of strontium titanate and ceria have been deposited by CCVD on textured nickel substrates and optimized to appropriate thicknesses and microstructures to provide templates for growing PLD YBCO with high critical current density values. The CCVD buffer layers have been scaled to meter plus lengths with good epitaxial uniformity along the length. A short sample cut from one of the lengths enabled high critical current density PLD YBCO. Films of CCVD YBCO superconductors have been grown on single crystal substrates with critical current densities over 1 MA/cm2. Work is currently in progress to combine both the buffer layer and superconductor technologies to produce high-quality coupons of HTS tape made entirely by the non-vacuum CCVD process.

Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

2021 ◽  
Vol 42 (12) ◽  
pp. 122804
Author(s):  
Shangfeng Liu ◽  
Ye Yuan ◽  
Shanshan Sheng ◽  
Tao Wang ◽  
Jin Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Flat Surface ◽  
Epitaxial Lateral Overgrowth ◽  
High Temperature Annealing ◽  
High Quality ◽  
High Crystalline Quality ◽  
X Ray ◽  
Lateral Overgrowth

Abstract In this work, based on physical vapor deposition and high-temperature annealing (HTA), the 4-inch crack-free high-quality AlN template is initialized. Benefiting from the crystal recrystallization during the HTA process, the FWHMs of X-ray rocking curves for (002) and (102) planes are encouragingly decreased to 62 and 282 arcsec, respectively. On such an AlN template, an ultra-thin AlN with a thickness of ~700 nm grown by MOCVD shows good quality, thus avoiding the epitaxial lateral overgrowth (ELOG) process in which 3–4 μm AlN is essential to obtain the flat surface and high crystalline quality. The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED, therefore significantly improving yields and decreasing cost.

High-mobility two-dimensional electron gases in Si/SiGe heterostructures on relaxed SiGe layers grown at high temperature

1997 ◽  
Vol 12 (8) ◽  
pp. 943-946 ◽  
Author(s):  
A C Churchill ◽  
D J Robbins ◽  
D J Wallis ◽  
N Griffin ◽  
D J Paul ◽  
...  
Keyword(s):  
High Temperature ◽  
High Mobility ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Electron Gases

scholarly journals Direct Growth of Antimonene on C-Plane Sapphire by Molecular Beam Epitaxy

2020 ◽  
Vol 10 (2) ◽  
pp. 639
Author(s):  
Minghui Gu ◽  
Chen Li ◽  
Yuanfeng Ding ◽  
Kedong Zhang ◽  
Shunji Xia ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Molecular Beam Epitaxy ◽  
Sapphire Substrate ◽  
Molecular Beam ◽  
Three Dimensional ◽  
High Mobility ◽  
Two Dimensional ◽  
Large Area ◽  
High Quality ◽  
Direct Growth

Monolayer antimony (antimonene) has been reported for its excellent properties, such as tuneable band gap, stability in the air, and high mobility. However, growing high quality, especially large-area antimonene, remains challenging. In this study, we report the direct growth of antimonene on c-plane sapphire substrate while using molecular beam epitaxy (MBE). We explore the effect of growth temperature on antimonene formation and present a growth phase diagram of antimony. The effect of antimony sources (Sb2 or Sb4) and a competing mechanism between the two-dimensional (2D) and three-dimensional (3D) growth processes and the effects of adsorption and cracking of the source molecules are also discussed. This work offers a new method for growing antimonene and it provides ideas for promoting van der Waals epitaxy.

Novel Gate Insulator Process by Nitrogen Annealing for Si-Face SiC MOSFET with High-Mobility and High-Reliability

2018 ◽  
Vol 924 ◽  
pp. 457-460 ◽  
Author(s):  
Shunsuke Asaba ◽  
Tatsuo Schimizu ◽  
Yukio Nakabayashi ◽  
Shigeto Fukatsu ◽  
Toshihide Ito ◽  
...  
Keyword(s):  
High Temperature ◽  
Electric Field ◽  
Field Effect ◽  
High Reliability ◽  
High Mobility ◽  
Gate Insulator ◽  
Field Effect Mobility ◽  
High Quality ◽  
Bias Temperature Instability ◽  
Nitrogen Annealing

The gate insulator process for SiC-MOSFET was examined and high-quality interface was realized by employing the pre-annealing process before high-temperature N2 annealing. The pre-annealing evidently activated the interface to introduce nitrogen, and then field-effect mobility exceeded 50 cm2/Vs. The fabricated sample also demonstrated superior bias temperature instability (BTI) and excellent breakdown electric field of 11.7 MV/cm.

Metallic layered germanium phosphide GeP5 for high rate flexible all-solid-state supercapacitors

2018 ◽  
Vol 6 (40) ◽  
pp. 19409-19416 ◽  
Author(s):  
Bingchao Yang ◽  
Anmin Nie ◽  
Yukai Chang ◽  
Yong Cheng ◽  
Fusheng Wen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Pressure ◽  
High Temperature ◽  
Solid State ◽  
High Rate ◽  
Two Dimensional ◽  
Oriented Growth ◽  
High Quality ◽  
Growth Technique ◽  
High Temperature High Pressure

In this study, high quality GeP5 crystals with two-dimensional (2D) layered structures and novel electrical conductivity of 2.4 × 106 S m−1 have been prepared under high-temperature high-pressure oriented growth technique (HTHP-OGT).

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