scholarly journals Realization of the Kohn’s Theorem in Ge/Si Quantum Dots with Hole Gas: Theory and Experiment

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 56 ◽  
Author(s):  
Hayk A. Sarkisyan ◽  
David B. Hayrapetyan ◽  
Lyudvig S. Petrosyan ◽  
Eduard M. Kazaryan ◽  
Anton N. Sofronov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Molecular Beam ◽  
Far Infrared ◽  
Resonant Absorption ◽  
Experimental Results ◽  
Quantum Transitions ◽  
Si Quantum Dots ◽  
Specific Quantum ◽  
Good Agreement

This article discusses specific quantum transitions in a few-particle hole gas, localized in a strongly oblate lens-shaped quantum dot. Based on the adiabatic method, the possibility of realizing the generalized Kohn theorem in such a system is shown. The criteria for the implementation of this theorem in a lens-shaped quantum dot, fulfilled in the experiment, is presented. An analytical expression is obtained for the frequencies of resonant absorption of far-infrared radiation by a gas of heavy holes, which depends on the geometric parameters of the quantum dot. The results of experiments on far-infrared absorption in the arrays of p-doped Ge/Si quantum dots grown by molecular beam epitaxy (MBE) with gradually increasing average number of holes in dot are presented. Experimental results show that the Coulomb interaction between the holes does not affect the resonant frequency of the transitions. A good agreement between the theoretical and experimental results is shown.

Enhancement of efficiency and long-term stability in graphene/Si-quantum-dot heterojunction photodetectors by employing bis(trifluoromethanesulfonyl)-amide as a dopant for graphene

2017 ◽  
Vol 5 (48) ◽  
pp. 12737-12743 ◽  
Author(s):  
Dong Hee Shin ◽  
Chan Wook Jang ◽  
Ju Hwan Kim ◽  
Jong Min Kim ◽  
Ha Seung Lee ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Term Stability ◽  
Long Term Stability ◽  
Si Quantum Dot ◽  
First Time ◽  
Si Quantum Dots

Bis(trifluoromethanesulfonyl)-amide (TFSA) is for the first time employed as a dopant for graphene for graphene/Si-quantum-dots-based photodetectors.

SELF-ORGANIZED QUANTUM DOTS

2002 ◽  
Vol 12 (01) ◽  
pp. 45-78 ◽  
Author(s):  
A. R. WOLL ◽  
P. RUGHEIMER ◽  
M. G. LAGALLY
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Self Assembly ◽  
The Self ◽  
Experimental Results ◽  
Size Distributions ◽  
Ongoing Research ◽  
Kinetics And Thermodynamics ◽  
Self Organized ◽  
Formation And Evolution

We review the concepts and principal experimental results pertaining to the self-assembly and self-ordering of quantum dots in semiconductor systems. We focus on the kinetics and thermodynamics of the formation and evolution of coherently strained 3D islands, and the effects of strain on nucleation, growth, and island shape. We also discuss ongoing research on methods to control the density, size, and size distributions of strained islands, both within a single strained layer and in quantum dot (QD) multilayers.

Heterostructures with self-organized quantum dots of Ge on Si for optoelectronic devices

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
K. Lozovoy ◽  
A. Voytsekhovskiy ◽  
A. Kokhanenko ◽  
V. Satdarov ◽  
O. Pchelyakov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam ◽  
Optoelectronic Devices ◽  
Growth Conditions ◽  
Size Distribution Function ◽  
Self Organized ◽  
Segregation Effect ◽  
Infra Red ◽  
Complex Mathematical Model ◽  
Si Quantum Dots

AbstractIn this paper an analysis of tendencies of Ge on Si quantum dots nanoheterostructures’ usage in different optoelectronic devices such as, for example, solar cells and photodetectors of visible and infra-red regions is carried out; a complex mathematical model for calculation of dependency on growth conditions of self-organized quantum dots of Ge on Si grown using the method of molecular beam epitaxy parameters is described. Ways of segregation effect and underlying layers’ influence are considered. It is shown that for realization of good device characteristics quantum dots should have high density, small sizes, uniformity, and narrow size distribution function. The desirable parameters of arrays of square and rectangular quantum dots for device application are attainable under certain growth conditions.

OPTICAL AND STRUCTURAL ANALYSIS OF Ge/Si QUANTUM DOTS GROWN ON A Si(001) SURFACE COVERED WITH A SiO2 SUB-MONOLAYER

2007 ◽  
Vol 06 (03n04) ◽  
pp. 245-248
Author(s):  
A. FONSECA ◽  
E. ALVES ◽  
J. P. LEITÃO ◽  
N. A. SOBOLEV ◽  
M. C. CARMO ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam ◽  
Broad Band ◽  
Sample Surface ◽  
High Energy ◽  
Scanning Tunneling ◽  
Hydrogen Passivation ◽  
Tunneling Microscopy ◽  
Grazing Angles ◽  
Si Quantum Dots

In this work we performed measurements of photoluminescence (PL), scanning tunneling microscopy (STM), and Rutherford backscattering (RBS) at grazing angles of incidence in a set of samples grown by molecular beam epitaxy, in which a Ge layer was deposited on a Si (001) substrate covered with a thin SiO 2 layer. Three different thicknesses for either layer were deposited: 0.5, 0.75 or 1 monolayer (ML) of SiO 2, and 0.3, 0.6 or 0.9 nm of Ge . The PL measurements for the samples with thicker layers show a broad band at ~ 0.85 eV superimposed on a dislocation related band at ~ 0.81 eV . The attribution of the high energy band to Ge islands in this sample is supported by STM and RBS measurements, as well as by PL measurements after hydrogen passivation of the sample surface. For the samples with thinner SiO 2 and Ge layers, no evidence for the formation of Ge islands was found.

scholarly journals Two-colour Three-pulse Spectrally Resolved Nonlinear Spectroscopy for Studies of Dynamics in Semiconductor Si Quantum Dots

2020 ◽  
Vol 30 (1) ◽  
pp. 79
Author(s):  
Vuong Van Cuong ◽  
Dinh Ba Khuong ◽  
Dao Van Lap
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Optical Phonon ◽  
Acoustic Phonon ◽  
Nonlinear Spectroscopy ◽  
Transverse Optical ◽  
Transverse Acoustic ◽  
Spectrally Resolved ◽  
Si Quantum Dots

We demonstrate that a two-colour three-pulsenonlinear spectroscopy can be used to study the dynamics of excited carriers inSi quantum dot structures embedded in SiN. Decays of the transverse optical phonon population and the transverse acoustic phonon population are measured and discussed. A simple theoretical modelis also used to support interpretation of our experimental observations.

Size-controlled Si quantum dots embedded in B-doped SiNx/Si3N4 superlatice for Si quantum dot solar cells

2016 ◽  
Vol 28 (2) ◽  
pp. 1322-1327 ◽  
Author(s):  
Xiaobo Chen ◽  
Wen Yang ◽  
Peizhi Yang ◽  
Junbao Yuan ◽  
Fei Zhao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Quantum Dot ◽  
Si Quantum Dot ◽  
Quantum Dot Solar Cells ◽  
Size Controlled ◽  
Si Quantum Dots
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