Exciton spectroscopy with spatially separated electron and hole in Ge/Si heterostructure with germanium quantum dots

2018 ◽  
Vol 44 (8) ◽  
pp. 819-823 ◽  
Author(s):  
S. I. Pokutnyi
Keyword(s):  
Quantum Dots ◽  
Germanium Quantum Dots ◽  
Exciton Spectroscopy

scholarly journals Synthesis, Surface Modification and Purification of Silicon and Germanium Quantum Dots for Biological Applications

2021 ◽  
Author(s):  
◽  
Amane Shiohara
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Silica Nanoparticles ◽  
Microemulsion System ◽  
Biological Applications ◽  
Silicon Quantum Dots ◽  
Surface Molecules ◽  
Silicon And Germanium ◽  
Germanium Quantum Dots ◽  
Oxygen Atoms

<p>Quantum dots have applications in biomedical fields such as bio-imaging and drug delivery systems. This thesis describes research on silicon and germanium nanoparticles (quantum dots) synthesis and surface modification for biological applications. Purification methods of these quantum dots were also explored. In chapter 6 the application of silica nanoparticles into dry eye diagnosis was studied. The purpose of this research is to contribute the application of nanotechnology into biological fields. The crystalinity of the quantum dots was characterised by Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction analysis (SAED). The molecules on the surface of the quantum dots were characterised by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR).  Silicon quantum dots were synthesised with a microemulsion system and various types of molecules were attached on the surface of the silicon quantum dots. However, some of the capping molecules which have oxygen atoms tend to form bonds between oxygen and silicon. Therefore, in the later chapter (chapter 4) various chemical reactions were conducted on the molecules attached to the silicon quantum dots. The silicon quantum dots were capped with diene molecules and one of the double bonds was left on the terminal end. The terminal end double bonds were converted to the functional groups which contain oxygen atoms to form peptide bonds. In this way it was confirmed that it can reduce the risk of oxygen atoms to be attached on the surface of the silicon quantum dots. The molecules on the surface of the silicon quantum dots were characterised mainly by FTIR and ¹H NMR. Optical properties and cyto-toxicity of these silicon quantum dots were also measured and analysed depending on the surface molecules.  Two synthetic approaches were taken to produce germanium quantum dots. The first approach was the microemulsion system at room temperature. Different combinations of the surfactant and capping molecules were tested. For the second approach, high temperature bench top system was applied. In this method the bio-friendly molecules which have high boiling points were chosen as capping agents. The surface molecules were characterised by FTIR spectroscopy.  In chapter 6 the synthesis of dye molecules conjugated silica nanoparticles was described. The purpose of this research is to produce biologically safe nanoparticles which can be applied in dry eye diagnosis. Three different dyes were used to conjugate with the silica nanoparticles. Only fluorescein isothiocyanate (FITC) succeeded in conjugating with the nanoparticles. Optical properties of this sample were measured and compared with the free dye molecule. Also the sample was applied in human eyes to analyse the tear film layer.  An overall conclusion and future plans for the research were given in the last chapter.In this chapter, ideas of overcoming the problems and improving the techniques conducted in the research were described.</p>

scholarly journals Experiments towards size and dopant control of germanium quantum dots for solar applications

2015 ◽  
Vol 3 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Brittany L. Oliva-Chatelain ◽  
◽  
Andrew R. Barron
Keyword(s):  
Quantum Dots ◽  
Germanium Quantum Dots ◽  
Solar Applications

High-density one-dimensional well-aligned germanium quantum dots on a nanoridge array

2008 ◽  
Vol 93 (8) ◽  
pp. 083101 ◽  
Author(s):  
Yan-Ru Chen ◽  
Chieh-Hsiung Kuan ◽  
Yuen-Wuu Suen ◽  
Yu-Hwa Peng ◽  
Peng-Shiu Chen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Density ◽  
One Dimensional ◽  
Germanium Quantum Dots

Third order optical nonlinearity investigation of germanium quantum dots embedded in silica matrix

2017 ◽  
Author(s):  
Liangmin Zhang ◽  
David Bishel ◽  
William Cheung ◽  
Joseph Mini ◽  
Salvador Montes ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Nonlinearity ◽  
Silica Matrix ◽  
Third Order ◽  
Germanium Quantum Dots

Coupling of Germanium Quantum Dots with Collective Sub-radiant Modes of Silicon Nanopillar Arrays

ACS Photonics ◽  
2020 ◽  
Author(s):  
Viktoriia Rutckaia ◽  
Frank Heyroth ◽  
Georg Schmidt ◽  
Alexey Novikov ◽  
Mikhail Shaleev ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Germanium Quantum Dots ◽  
Nanopillar Arrays

Investigation of Epitaxial Overgrowth on Germanium Quantum Dots

2001 ◽  
Vol 676 ◽  
Author(s):  
David W. Greve ◽  
Qian Zhao
Keyword(s):  
Quantum Dots ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Reciprocal Space Mapping ◽  
Silicon Epitaxial Layer ◽  
Germanium Quantum Dots ◽  
Uniform Quantum

ABSTRACTWe report on the characterization of germanium quantum dots grown on silicon (001) substrates by ultra-high vacuum chemical vapor deposition (UHV/CVD). In many applications small and uniform quantum dots are required which must be overgrown by a silicon epitaxial layer. We report here on the effect of carbon predeposition from methylsilane on the dot size and uniformity. In addition, we use reciprocal space mapping to evaluate the qualityof epitaxial layers which overgrow the quantum dots. The results show some differences from previous reports on MBE-grown dots.

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