Growth of InAs Quantum Dots on a Low Lattice-Mismatched AlGaSb Layer Prepared on GaAs (001) Substrates

2004 ◽  
Vol 99-100 ◽  
pp. 49-54 ◽  
Author(s):  
N. Yamamoto ◽  
K. Akahane ◽  
S. Gozu ◽  
Noboru Ohtani
Keyword(s):  
Quantum Dots ◽  
Communication Networks ◽  
Optical Communication ◽  
Growth Conditions ◽  
Average Density ◽  
Average Height ◽  
Growth Technique ◽  
Long Wavelength ◽  
Atomic Force ◽  
Structural Selectivity

Optical communication wavelength emissions from the quantum dots (QDs) structures prepared on (001)-oriented GaAs substrates are discussed. A new growth technique of low-stressed InAs QDs on the AlGaSb layer in a low lattice-mismatched (1.3%) InAs/AlGaSb system is presented. The average height and diameter of the 4-ML InAs QDs on AlGaSb are evaluated to 5.8 nm and 45.2 nm respectively with an average density of 2.18 x 1010 /cm2 using atomic force microscope (AFM) measurements. There is structural selectivity between the QDs layer and the flat hetero-interface under changing growth conditions in the InAs/AlGaSb system. Long-wavelength PL emissions around 1.3 µm and 1.55 µm can be achieved by embedding InAs QDs in AlGaSb layers. Therefore it is expected that low-stressed InAs QDs grown on a AlGaSb layer prepared on a GaAs substrate will be useful in the fabrication of novel QDs devices for optical-communication networks.

GaInAsP/InP ORGANOMETALLIC VAPOR PHASE EPITAXY FOR RESEARCH AND FABRICATION OF DEVICES

1990 ◽  
Vol 01 (03n04) ◽  
pp. 347-367 ◽  
Author(s):  
KAZUHITO FURUYA ◽  
YASUYUKI MIYAMOTO
Keyword(s):  
Quantum Well ◽  
Single Crystal ◽  
Vapor Phase ◽  
Optical Communication ◽  
Ballistic Transport ◽  
Growth Conditions ◽  
Vapor Phase Epitaxy ◽  
Quantum Well Lasers ◽  
Organometallic Vapor Phase Epitaxy ◽  
Growth Technique

GaInAsP/InP organometallic vapor phase epitaxy (OMVPE) is widely used for the fabrication of lasers and detectors used in optical communication. Here we describe the apparatus and growth technique of OMVPE and point out important growth conditions to obtain device quality single-crystal materials. Our research includes the use of OMVPE for the study of quantum-well lasers, ballistic-transport electron devices and nanometer heterostructures.

Mini droplets to super droplets: evolution of self-assembled Au droplets on GaAs(111)B and (110)

2014 ◽  
Vol 47 (2) ◽  
pp. 505-510 ◽  
Author(s):  
Mao Sui ◽  
Ming-Yu Li ◽  
Eun-Soo Kim ◽  
Jihoon Lee
Keyword(s):  
Growth Parameters ◽  
Average Diameter ◽  
Growth Conditions ◽  
Average Density ◽  
Minor Effect ◽  
Average Height ◽  
Deposition Amount ◽  
Self Assembled ◽  
A Minor ◽  
20 Nm

In this article, the effect of deposition amount on self-assembled Au droplets fabricated on GaAs(111)B and (110) is presented. The investigation is systematically performed by the variation of the Au deposition amount from 2 to 20 nm while fixing the other growth parameters such as annealing temperature and duration to clearly observe the effect. Under identical growth conditions, the self-assembled Au droplets show significantly different size and density depending on the amount of Au deposition:i.e.the average height varies by 436% from 21.8 to 95.5 nm and the average diameter swings by 827% from 52 to 430 nm, showing that the size increase is dominated by the lateral expansion. Meanwhile the average density varies by over two orders of magnitude from 1.24 × 108to 4.48 × 1010 cm−2on GaAs(111)B. With relatively low Au deposition amounts, below 3 nm, round dome-shaped mini Au droplets with high packing density can be fabricated, while super large Au droplets result with higher deposition amounts, above 10 nm, with a density two orders of magnitude lower. It is also found that the surface index has a minor effect on the fabrication of self-assembled Au droplets with the variation of deposition amount. The results are systematically analyzed and discussed in terms of atomic force microscopy and scanning electron microscopy images, line profiles, power spectrums, r.m.s. surface roughness, and size and density plots.

Atomic Force Microscopy and Spectroscopy of Self-Assembled InAsSb Quantum Dots grown on InP Substrates by MOCVD

2004 ◽  
Vol 829 ◽  
Author(s):  
Yongkun Sin ◽  
Hyun I. Kim ◽  
Gary W. Stupian ◽  
Yueming Qiu
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Light Sources ◽  
Photoluminescence Intensity ◽  
Atomic Force ◽  
Self Assembled ◽  
Inp Substrates

ABSTRACTInAsSb quantum dot (QD) lasers are promising light sources with emission wavelengths beyond 2μm as recently demonstrated. We report the first detailed atomic force microscope (AFM) characterization of uncapped InAsSb quantum dots self-assembled on GaAs/In0.53Ga0.47As layers. These quantum dot structures are grown on (100) InP substrates by metal organic chemical vapor deposition (MOCVD). Growth conditions are chosen to maximize photoluminescence intensity and to obtain high output powers from Fabry-Perot lasers with one stack of InAsSb QDs. Conductive AFM is employed to simultaneously study topography, current image, and current-voltage (I-V) characteristics from various InAs1-ySby QDs with y varied between 0 and 0.25. Typical dot density is 4–5×1010/cm2 and dots are estimated to have a lateral dimension at the base of ∼40nm and a height of 2–5nm. I-V characteristics measured from individual InAsSb QDs are compared to those from InAs QDs. Also reported are electronic properties including energy band gaps of InAs and InAsSb QDs.

scholarly journals Design of Tunable Holographic Liquid Crystalline Diffraction Gratings

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6789
Author(s):  
Katarzyna A. Rutkowska ◽  
Anna Kozanecka-Szmigiel
Keyword(s):  
Liquid Crystal ◽  
Communication Networks ◽  
Optical Communication ◽  
Liquid Crystalline ◽  
Incident Light ◽  
Diffraction Gratings ◽  
Lagrange Equations ◽  
Experimental Conditions ◽  
Molecular Distribution ◽  
Polarization Gratings

Tunable diffraction gratings and phase filters are important functional devices in optical communication and sensing systems. Polarization gratings, in particular, capable of redirecting an incident light beam completely into the first diffraction orders may be successfully fabricated in liquid crystalline cells assembled from substrates coated with uniform transparent electrodes and orienting layers that force a specific molecular distribution. In this work, the diffraction properties of liquid crystal (LC) cells characterized by a continually rotating cycloidal director pattern at the cell substrates and in the bulk, are studied theoretically by solving a relevant set of the Euler-Lagrange equations. The electric tunability of the gratings is analyzed by estimating the changes in liquid crystalline molecular distribution and thus in effective birefringence, as a function of external voltage. To the best of our knowledge, such detailed numerical calculations have not been presented so far for liquid crystal polarization gratings showing a cycloidal director pattern. Our theoretical predictions may be easily achieved in experimental conditions when exploiting, for example, photo-orienting material, to induce a permanent LC alignment with high spatial resolution. The proposed design may be for example, used as a tunable passband filter with adjustable bandwidths, thus allowing for potential applications in optical spectroscopy, optical communication networks, remote sensing and beyond.

Ingan Quantum Dots Fabricated On Aigan Surfaces -Growth Mechanism And Optical Propertiesh-

1997 ◽  
Vol 482 ◽  
Author(s):  
H. Hirayama ◽  
S. Tanaka ◽  
P. Ramvall ◽  
Y. Aoyagi
Keyword(s):  
Quantum Dots ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Energy Shift ◽  
Organic Chemical ◽  
Self Assembling ◽  
Atomic Force ◽  
Peak Energy ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

AbstractWe demonstrate photoluminescence from self- assembling InGaN quantum dots (QDs), which are artificially fabricated on AlGaN surfaces via metal- organic chemical vapor deposition. InGaN QDs are successfully fabricated by the growth mode transition from step- flow to three dimensional island formation by using anti-surfactant silicon on AlGaN surface. The diameter and height of the fabricated InGaN QDs are estimated to be ˜10nm and ˜5nm, respectively, by an atomic- force- microscope (AFM). Indium mole fraction of InxGal−x N QDs is controlled from x=˜0.22 to ˜0.52 by varying the growth temperature of QDs. Intense photoluminescence is observed even at room temperature from InGaN QDs embedded with the GaN capping layers. In addition, the temperature- dependent energy shift of the photoluminescence peak- energy shows a localization behavior.

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