High Quality GaAs on Soi by MOCVD

1989 ◽  
Vol 160 ◽  
Author(s):  
N.H. Karam ◽  
V. Haven ◽  
S. Vernon ◽  
J. Ramdani ◽  
N. El-Masry ◽  
...  
Keyword(s):  
Thermal Cycle ◽  
Defect Density ◽  
Fold Increase ◽  
Gate Length ◽  
Photoluminescence Intensity ◽  
Large Area ◽  
High Quality ◽  
Cycle Growth ◽  
Gaas Films ◽  
Low Temperature Photoluminescence

AbstractEpitaxial GaAs films have been successfully deposited on three-inch Si wafers with a buried oxide by MOCVD. The SOI wafers were prepared using Separation by IMplantation of OXygen (SIMOX) process. High quality GaAs on SIMOX films, with dislocation density in the range of 2–6 × 106 cm-2, have been achieved using Thermal Cycle Growth (TCG) deposition technique. These films showed a 50-fold increase in the low temperature photoluminescence intensity over conventional deposition. We have also fabricated MESFET’s in GaAs on SIMOX with performance comparable to those fabricated in GaAs. The maximum measured transconductance was in the range of 175-180 ms/mm at a 1.5 µm gate length and a 5 µm source to drain separation. This is the first demonstration of large area, high quality and low defect density GaAs on SIMOX.

Growth and Characterization of InP/GaAs on Soi by Mocvd

1990 ◽  
Vol 198 ◽  
Author(s):  
N.H. Karam ◽  
V. Haven ◽  
S.M. Vernon ◽  
F. Namavar ◽  
N. El-Masry ◽  
...  
Keyword(s):  
Thermal Cycle ◽  
Defect Density ◽  
Photoluminescence Intensity ◽  
Defect Reduction ◽  
Reduction Techniques ◽  
Thermal Cycle Annealing ◽  
Cycle Growth ◽  
Order Of Magnitude ◽  
First Time

ABSTRACTEpitaxial InP films have been successfully deposited on GaAs coated silicon wafers with a buried oxide for the first time by MOCVD. The SOI wafers were prepared using the Separation by IMplantation of Oxygen (SIMOX) process. The quality of InP on SIMOX is comparable to the best of InP on Si deposited in the same reactor. Preliminary results on defect reduction techniques such as Thermal Cycle Growth (TCG) show an order of magnitude increase in the photoluminescence intensity and a factor of five reduction in the defect density. TCG has been found more effective than Thermal Cycle Annealing (TCA) in improving the crystalline perfection and optical properties of the deposited films.

Large Grained, Low Defect Density Polycrystalline Silicon on Glass Substrates by Large-area Diode Laser Crystallisation

2012 ◽  
Vol 1426 ◽  
pp. 251-256 ◽  
Author(s):  
Bonne Eggleston ◽  
Sergey Varlamov ◽  
Jialiang Huang ◽  
Rhett Evans ◽  
Jonathon Dore ◽  
...  
Keyword(s):  
Diode Laser ◽  
Polycrystalline Silicon ◽  
Crystalline Silicon ◽  
Defect Density ◽  
Open Circuit ◽  
Large Area ◽  
High Quality ◽  
Glass Substrates ◽  
Silicon Thin Films ◽  
Open Circuit Voltages

ABSTRACTA new method to form high quality crystalline silicon thin films on cheap glass substrates is developed using a single pass of a line-focus cw diode laser in air. The laser process results in the formation of large high-quality crystals as they grow laterally in the scan direction – seeded by the previously crystallised region. Grains 10 μm in thickness, up to millimetres in length and hundreds of microns in width have been grown with virtually zero detectable intragrain defects. Another mode is found which results in much smaller crystals grown by partial melting. The dominant grain boundaries identified are Σ3 <111> 60° twins. Hall mobilities as high as 470 cm2/Vs have been recorded. A diffused emitter is used to create a p-n junction at the rear of the films which produces open-circuit voltages as high as 539 mV.

Porous SiC Substrate Materials for High-Quality Epitaxial and Bulk Growth

1999 ◽  
Vol 587 ◽  
Author(s):  
M. Mynbaeva ◽  
N. Savkina ◽  
A. Zubrilov ◽  
N. Seredova ◽  
M. Scheglov ◽  
...  
Keyword(s):  
Stress Reduction ◽  
Defect Density ◽  
Deep Level ◽  
Epitaxial Lateral Overgrowth ◽  
Large Area ◽  
High Quality ◽  
Density Reduction ◽  
Lateral Overgrowth ◽  
Sublimation Method ◽  
Porous Sic

AbstractThe main unsolved problem in SiC technology is a high density of defects in substrate materials (micropipes and dislocations) propagating into device structures and causing device failure. Recently, significant progress in defect density reduction in semiconductor materials has been achieved using epitaxial lateral overgrowth techniques. In this paper, we describe a novel technique, which shows a high potential for defect reduction in epitaxial and bulk SiC. This technique is based on nano-scale epitaxial lateral overgrowth (NELOG) method, which employs porous substrate materials. Usually, the pores are from 50 to 500 nm in size and epitaxial material overgrowing these pores, forms continues high-quality layer. It is important that the NELOG method does not require any mask. This technique may be easily scaled for large area substrates.In this work, SiC layers were grown on porous SiC by sublimation method, which is widely used for both epitaxial and bulk SiC growth. Porous SiC substrates were formed by surface anodization of SiC commercial wafers. It was shown that SiC layers grown on porous SiC substrates have smooth surface and high crystal quality. The surface of overgrown material was uniform and flat without any traces of porous structure. X-ray topography indicated significant defect density and stress reduction in SiC grown on porous material. Photoluminescence measurements showed a reduction of deep level recombination in SiC.

Zno Nanorod Synthesis via Controlled ZnO Seed Layer by Filtered Pulse Cathodic Vacuum Arc: Luminescence Enhancement

2013 ◽  
Vol 802 ◽  
pp. 1-6
Author(s):  
Anumut Deachana ◽  
Paul K. Chu ◽  
Dheerawan Boonyawan
Keyword(s):  
Seed Layer ◽  
Energy Gap ◽  
Defect Density ◽  
Zno Nanorods ◽  
Vacuum Arc ◽  
Zno Nanorod ◽  
Large Area ◽  
High Quality ◽  
Continuous Growth ◽  
Seed Layers

A simple synthesis route to high-quality ZnO nanorod is reported, utilizing ZnO thin films grown by Filtered Pulse Cathodic Vacuum Arc (FPCVA) deposition as seed layers and continuous growth by hydrothermal method. Depending upon the FPCVA deposited conditions, implanted voltages, thickness and annealing temperature of ZnO seed layer, the surface morphology of the ZnO nanorod on ZnO film was noticeably different. The average diameters of the nanorod on Al substrates varied from about 131.99 ± 23.87 to 418.17 ±75.50 nm. The grown ZnO nanorod showed a high crystallinity with energy gap of 3.37 eV and low defect density confirmed by UV/VIS Spectrometer and photoluminescence spectrum (PL). Large-area growth, quasi-aligned and high quality indicates that the ZnO nanorods produced have potential application in field emission and optoelectronic devices.

scholarly journals 2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hitesh Agarwal ◽  
Bernat Terrés ◽  
Lorenzo Orsini ◽  
Alberto Montanaro ◽  
Vito Sorianello ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hafnium Oxide ◽  
High Speed ◽  
Hexagonal Boron Nitride ◽  
Temperature Stability ◽  
Cost Effective ◽  
Fold Increase ◽  
Building Blocks ◽  
High Quality ◽  
New Device

AbstractElectro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs.

Large-area synthesis of high-quality β-MnO2nanowires and the mechanism of formation through a facile mineralization process

2005 ◽  
Vol 16 (10) ◽  
pp. 2072-2076 ◽  
Author(s):  
Fu Zhou ◽  
Huagui Zheng ◽  
Xuemei Zhao ◽  
Qixun Guo ◽  
Xiaomin Ni ◽  
...  
Keyword(s):  
Mechanism Of Formation ◽  
Large Area ◽  
Mineralization Process ◽  
High Quality

scholarly journals Ambient Air Temperature Assisted Crystallization for Inorganic CsPbI2Br Perovskite Solar Cells

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3398
Author(s):  
Yi Long ◽  
Kun Liu ◽  
Yongli Zhang ◽  
Wenzhe Li
Keyword(s):  
Solar Cells ◽  
Air Temperature ◽  
High Performance ◽  
Defect Density ◽  
Perovskite Solar Cells ◽  
Ambient Air ◽  
Dark Phase ◽  
High Quality ◽  
Ambient Air Temperature ◽  
Air Atmosphere

Inorganic cesium lead halide perovskites, as alternative light absorbers for organic–inorganic hybrid perovskite solar cells, have attracted more and more attention due to their superb thermal stability for photovoltaic applications. However, the humid air instability of CsPbI2Br perovskite solar cells (PSCs) hinders their further development. The optoelectronic properties of CsPbI2Br films are closely related to the quality of films, so preparing high-quality perovskite films is crucial for fabricating high-performance PSCs. For the first time, we demonstrate that the regulation of ambient temperature of the dry air in the glovebox is able to control the growth of CsPbI2Br crystals and further optimize the morphology of CsPbI2Br film. Through controlling the ambient air temperature assisted crystallization, high-quality CsPbI2Br films are obtained, with advantages such as larger crystalline grains, negligible crystal boundaries, absence of pinholes, lower defect density, and faster carrier mobility. Accordingly, the PSCs based on as-prepared CsPbI2Br film achieve a power conversion efficiency of 15.5% (the maximum stabilized power output of 15.02%). Moreover, the optimized CsPbI2Br films show excellent robustness against moisture and oxygen and maintain the photovoltaic dark phase after 3 h aging in an air atmosphere at room temperature and 35% relative humidity (R.H.). In comparison, the pristine films are completely converted to the yellow phase in 1.5 h.

On‐axis dc magnetron sputtering of large area high quality YBa2Cu3O7superconducting thin films

1992 ◽  
Vol 61 (3) ◽  
pp. 348-350 ◽  
Author(s):  
Y. Z. Zhang ◽  
L. Li ◽  
Y. Y. Zhao ◽  
B. R. Zhao ◽  
J. W. Li ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Dc Magnetron Sputtering ◽  
Large Area ◽  
High Quality

CVD growth of high-quality and large-area continuous h-BN thin films directly on stainless-steel as protective coatings

2021 ◽  
pp. 100135
Author(s):  
Shuai Jia ◽  
Weibing Chen ◽  
Jing Zhang ◽  
Chen-Yang Lin ◽  
Hua Guo ◽  
...  
Keyword(s):  
Thin Films ◽  
Stainless Steel ◽  
Protective Coatings ◽  
Large Area ◽  
High Quality ◽  
Cvd Growth

Material and optical properties of GaAs grown on (001) Ge/Si pseudo-substrate

2004 ◽  
Vol 809 ◽  
Author(s):  
Yves Chriqui ◽  
Ludovic Largeau ◽  
Gilles Patriarche ◽  
Guillaume Saint-Girons ◽  
Sophie Bouchoule ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dislocation Density ◽  
High Speed ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Lattice Parameter ◽  
Photoluminescence Intensity ◽  
High Quality ◽  
Light Emitting ◽  
Thermal Expansion Coefficients

ABSTRACTOne of the major challenges during recent years was to achieve the compatibility of III-V semiconductor epitaxy on silicon substrates to combine opto-electronics with high speed circuit technology. However, the growth of high quality epitaxial GaAs on Si is not straightforward due to the intrinsic differences in lattice parameters and thermal expansion coefficients of the two materials. Moreover, antiphase boundaries (APBs) appear that are disadvantageous for the fabrication of light emitting devices. Recently the successful fabrication of high quality germanium layers on exact (001) Si by chemical vapor deposition (CVD) was reported. Due to the germanium seed layer the lattice parameter is matched to the one of GaAs providing for excellent conditions for the subsequent GaAs growth. We have studied the material morphology of GaAs grown on Ge/Si PS using atomic layer epitaxy (ALE) at the interface between Ge and GaAs. We present results on the reduction of APBs and dislocation density on (001) Ge/Si PS when ALE is applied. The ALE allows the reduction of the residual dislocation density in the GaAs layers to 105 cm−2 (one order of magnitude as compared to the dislocation density of the Ge/Si PS). The optical properties are improved (ie. increased photoluminescence intensity). Using ALE, light emitting diodes based on strained InGaAs/GaAs quantum well as well as of In(Ga)As quantum dots on an exactly oriented (001) Ge/Si pseudo-substrate were fabricated and characterized.

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