scholarly journals Photoreflectance study of the GaAs buffer layer in InAs/GaAs quantum dots

2017 ◽  
Vol 30 (4) ◽  
pp. 56-60
Author(s):  
Diego Javier Sánchez Trujillo ◽  
Jhon Jairo Prías Barragán ◽  
Hernando Ariza Calderón ◽  
Álvaro Orlando Pulzara Mora ◽  
Máximo López López
Keyword(s):  
Quantum Dots ◽  
Electric Field ◽  
Buffer Layer ◽  
Surface Passivation ◽  
Bending Energy ◽  
Gaas Sample ◽  
Band Bending ◽  
Gaas Buffer Layer ◽  
Order Of Magnitude ◽  
The Difference

GaAs buffer layer in InAs/GaAs quantum dots (QDs) was investigated by Photoreflectance (PR) technique at 300 K. PR spectra obtained were compared with commercial GaAs sample PR spectra, and they were analyzed by using the derivative Lorentzian functions as proposed by Aspnes in the middle field regimen. PR spectra in InAs/GaAs QDs sample was attributed to the photoreflectance response in the GaAs buffer layer. Band bending energies were calculated for laser intensities from 1 mW to 21 mW. The photoreflectance comparative study in the samples was realized considering the difference in the parameters: electric field on the surface, broadening parameter, energy gained by photoexcited carriers due to the electric field applied, frequency of light and heavy holes and band bending energy values. The results suggest that the presence of InAs quantum dots increases the light and heavy holes frequencies and the band bending energy values; and decreases the electric field on the surface, the broadening parameter and the energy gained by photoexcited carriers. We found that InAs QDs presence modifies the surface electrical field around one order of magnitude in the GaAs buffer layer and this behavior can be attributed to surface passivation.

Photoluminescence Intensity Enhancement of GaAs by Vapor-Deposited GaS: a Rational Approach to Surface Passivation

1992 ◽  
Vol 282 ◽  
Author(s):  
Phillip P. Jenkins ◽  
Aloysius F. Hepp ◽  
Michael B. Power ◽  
Andrew R. Macinnes ◽  
Andrew R. Barrontt
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Surface Recombination Velocity ◽  
Rational Approach ◽  
Cubic Phase ◽  
Photoluminescence Intensity ◽  
Band Bending ◽  
X Ray ◽  
Order Of Magnitude

ABSTRACTA two order-of-magnitude enhancement of photoluminescence intensity relative to untreated GaAs has been observed for GaAs surfaces coated with chemical vapor-deposited GaS. The increase in photoluminescence intensity can be viewed as an effective reduction in surface recombination velocity and/or band bending. The gallium cluster [(t-Bu)GaS]4 was used as a single-source precursor for the deposition of GaS thin films. The cubane core of the structurally-characterized precursor is retained in the deposited film producing a cubic phase. Furthermore, a near-epitaxial growth is observed for the GaS passivating layer. Films were characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron and Rutherford backscattering spectroscopies.

High quality InAs quantum dots grown on patterned Si with a GaAs buffer layer

2009 ◽  
Vol 20 (30) ◽  
pp. 305301 ◽  
Author(s):  
Y Wang ◽  
J Zou ◽  
Z M Zhao ◽  
Z Hao ◽  
K L Wang
Keyword(s):  
Quantum Dots ◽  
Buffer Layer ◽  
High Quality ◽  
Inas Quantum Dots ◽  
Gaas Buffer Layer

Fabrication and Luminescence of Etched Quantum Rings and Vertically Coupled Dots

1995 ◽  
Vol 406 ◽  
Author(s):  
G. E. Philippa ◽  
J. A. Mejia Galeana ◽  
C. Cassou ◽  
P. D. Wang ◽  
C. Guasch ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Beam ◽  
Electric Field ◽  
Emission Spectrum ◽  
Electron Beam Lithography ◽  
Electrical Contacts ◽  
Outer Diameter ◽  
Quantum Rings ◽  
Order Of Magnitude ◽  
Linewidth Broadening

AbstractThe fabrication of GaAs-GaAIAs coupled quantum dots and of quantum rings using electron beam lithography and dry etching is described. Coupled dots of physical diameter of 500 and 250 nm were fabricated and processed with top electrical contacts to apply an electric field. We show that the emission spectrum of coupled dots is modified by the electric field. Quantum rings of 400 nm outer diameter and wall thickness of 25 nm were fabricated. The emission spectrum from rings showed the quantum well emission shifted to higher energies and although its intensity decreased by about one order of magnitude there was little linewidth broadening.

Evidence of coupling between InAs self-assembled quantum dots in thin GaAs buffer layer

2005 ◽  
Vol 26 (1-4) ◽  
pp. 276-280 ◽  
Author(s):  
E.T. Cho ◽  
H.D. Lee ◽  
D.W. Lee ◽  
J.I. Lee ◽  
S.I. Jung ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Buffer Layer ◽  
Gaas Buffer Layer ◽  
Self Assembled

Site-controlled InAs quantum dots grown on a 55 nm thick GaAs buffer layer

2009 ◽  
Vol 95 (24) ◽  
pp. 243106 ◽  
Author(s):  
T. J. Pfau ◽  
A. Gushterov ◽  
J. P. Reithmaier ◽  
I. Cestier ◽  
G. Eisenstein ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Buffer Layer ◽  
Inas Quantum Dots ◽  
Gaas Buffer Layer

Enhancement of photoelectrochemical performance in ferroelectric films via the introduction of an Au buffer layer

2021 ◽  
Vol 42 (11) ◽  
pp. 112701
Author(s):  
Dawei Cao ◽  
Ming Li ◽  
Jianfei Zhu ◽  
Yanfang He ◽  
Tong Chen ◽  
...  
Keyword(s):  
Electric Field ◽  
Buffer Layer ◽  
Water Splitting ◽  
Charge Separation ◽  
Sol Gel ◽  
Ferroelectric Films ◽  
Photoelectrochemical Performance ◽  
Band Bending ◽  
Polarization Electric Field ◽  
Pec Water Splitting

Abstract The inefficient separation of photogenerated carriers has become a serious problem that limits the photoelectrochemical (PEC) performance of semiconductors. Herein, a sol-gel method was used to prepare BiFeO3 ferroelectric thin films with FTO and FTO/Au as substrates, respectively. The polarization electric field of the ferroelectric can more effectively separate the carriers generated in the photoelectrode. Meanwhile, the introduction of an Au buffer layer can reduce the resistance in the process of charge transfer, accelerate the carrier migration, and enhance the efficiency of the charge separation. Under light irradiation, Au/BiFeO3 photoelectrode exhibited an extraordinary improvement in PEC water splitting compared with BiFeO3. In addition, the ferroelectric polarization electric field causes band bending, which further accelerates the separation of electrons and holes and improves the PEC performance of the photoelectrode. This work promotes the effective application of ferroelectric films in PEC water splitting.

GaAs buffer layer morphology and lateral distributions of InGaAs quantum dots

2005 ◽  
Vol 23 (3) ◽  
pp. 1226 ◽  
Author(s):  
A. Roshko ◽  
T. E. Harvey ◽  
S. Y. Lehman ◽  
R. P. Mirin ◽  
K. A. Bertness ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Buffer Layer ◽  
Gaas Buffer Layer

Size control of InAs quantum dots on 2°-off GaAs (100) substrate by the thickness of GaAs buffer layer

2001 ◽  
Vol 223 (4) ◽  
pp. 450-455 ◽  
Author(s):  
Hyo Jin Kim ◽  
Young Ju Park ◽  
Eun Kyu Kim ◽  
Tae Whan Kim
Keyword(s):  
Quantum Dots ◽  
Buffer Layer ◽  
Size Control ◽  
Inas Quantum Dots ◽  
Gaas Buffer Layer
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