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This document discusses quantum dots, which are semiconductor nanoparticles that exhibit quantum mechanical properties due to their small size. Quantum dots can range in size from 2-10 nanometers and are composed of hundreds to thousands of atoms. The size of the quantum dot determines its color, with smaller dots emitting shorter wavelengths of light. There are several methods for producing quantum dots, including colloidal synthesis in solution and fabrication through CMOS technology. Potential applications of quantum dots include solar cells, biomedical imaging and sensors, LEDs, quantum computing, and memory devices.

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2015-2016 Sardam ZAGROS ABDULLRAHMAN OMA 2015-2016 QUANTUM DOT Soran University Faculty of Science Chemistry Department Third stage
Introduction Quantum dot are very tiny particlules on the order of a nanometer in siz, QDs are composed of hundred to thousands atoms. QD is a semiconductor who excition are confined in all three spatial dimension. Semiconductors are cornerstone of the electronics industry and make possible personal computers. And those semiconductor materials can be made from an element, such as Silicon,Germanium or a Compound,such as Cds. QDs can the different of color depending of the size. QDs special because they are so small 4,000,000 dots in take up 2cm, QDs formed when the dots is exposed to a pulse of light at the right wavelength and time, the electron is raised to an excited state, after that the electron back to the ground state, in the location of those electrons backs drop behind the dots, these dots then have the ability to glow. Changing these size the emitting color of quantum dots can be tuned, shorter quantum dots emitting shorter wavelength of light and bigger quantum dots emitting longer wavelength of light. The energy band gap is correlated with size, as the dimension of particle decrease, the energy increase. The height and energy difference between energy levels increase of quantum dot decrease, smaller Dot equal to the higher Energy those equal to the smaller Wavelength and Blue Color. History The early semiconductor work of Bell Labs in 1947 led to a whole revolution in electronics. The first discovered of Quantum dot in the form of Nanocrystals (Glass Crystals) early 1980 by Russian Physicist Ekimov. Application Solar cells, Biology (biosensors & imaging), Light emitting diodes (LEDs), Quantum computation, Flat-panel displays, Memory elements, Photodetectors and Lasers.ets Production There are several ways to confine excitons in semiconductors resulting in different methods to produce quantum dot.Quantum dots are grown by advanced epitaxial techniques or by ion implantation,or in Nano devices made by state of the art lithoraphice techniques,.
i- Colloidal Synthesis:- Colloidal semiconductor Nano crystal are synthesized from precursor compound dissolved in solutions , much like traditional chemical processes. i- Fabrication:- CMOS technology can be employed to fabricate silicon quantum dots. Ultra small (L=20 nm, W=20nm) CMOS transistors behave a single elecrone quantum dot, when operate at cryogenic temperature. ii- Electrochemical Assembly:- Highly ordered arrays of quantum dot may also be self assembled by electrochemical techniques, Atemplate is created by causing an ionic reaction at electrolyte metal interface Which result in the spontaneous assembly of nanostructures. Characterization Quantum dot can be characterized by two techniques: ii- Optical Characterization Electron microscopes and atonic force microscopes (AFM) are widely used for the optical characterization of the size of the qdots. For the cross section investigation of pdote structures, transmission electron microscopy (TEM) is the moste used Ii- Electrochemical Characterization: Qdots can be detected directly or indirectly by oxidatively dissolving the metal ion into aqueous metal ion and then electrochemically sensing the ions by using stripping voltammetry or potentiometry or electrochemical impedance spectroscopy (EIS) Conclusion (Discussion) Quantum dot can be synthesized to be essentially any size, and therefore, produce essentially any wavelength of light. The future looks bright and exiting on all the possible applications of Quantum dot. Quantum dote is Nano crystal made of semiconductor material that are small enough to exhibit quantum mechanical properties. There are several ways to confine in semiconductors resulting in different methods to produce quantum dot. Quantum dot formed when electron goes up in ground state to existed state after that this electron goes down to the ground state after extinction of light (energy) so in the location of electrons drop behind of spot or dot (hole) those hole are Quantum dots.
Reference http://www.asemblon.com/ http://www.worldenergyoutlook.org/ http://www.springer.com http://www.Accademy.com

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  • 1. 2015-2016 Sardam ZAGROS ABDULLRAHMAN OMA 2015-2016 QUANTUM DOT Soran University Faculty of Science Chemistry Department Third stage
  • 2. Introduction Quantum dot are very tiny particlules on the order of a nanometer in siz, QDs are composed of hundred to thousands atoms. QD is a semiconductor who excition are confined in all three spatial dimension. Semiconductors are cornerstone of the electronics industry and make possible personal computers. And those semiconductor materials can be made from an element, such as Silicon,Germanium or a Compound,such as Cds. QDs can the different of color depending of the size. QDs special because they are so small 4,000,000 dots in take up 2cm, QDs formed when the dots is exposed to a pulse of light at the right wavelength and time, the electron is raised to an excited state, after that the electron back to the ground state, in the location of those electrons backs drop behind the dots, these dots then have the ability to glow. Changing these size the emitting color of quantum dots can be tuned, shorter quantum dots emitting shorter wavelength of light and bigger quantum dots emitting longer wavelength of light. The energy band gap is correlated with size, as the dimension of particle decrease, the energy increase. The height and energy difference between energy levels increase of quantum dot decrease, smaller Dot equal to the higher Energy those equal to the smaller Wavelength and Blue Color. History The early semiconductor work of Bell Labs in 1947 led to a whole revolution in electronics. The first discovered of Quantum dot in the form of Nanocrystals (Glass Crystals) early 1980 by Russian Physicist Ekimov. Application Solar cells, Biology (biosensors & imaging), Light emitting diodes (LEDs), Quantum computation, Flat-panel displays, Memory elements, Photodetectors and Lasers.ets Production There are several ways to confine excitons in semiconductors resulting in different methods to produce quantum dot.Quantum dots are grown by advanced epitaxial techniques or by ion implantation,or in Nano devices made by state of the art lithoraphice techniques,.
  • 3. i- Colloidal Synthesis:- Colloidal semiconductor Nano crystal are synthesized from precursor compound dissolved in solutions , much like traditional chemical processes. i- Fabrication:- CMOS technology can be employed to fabricate silicon quantum dots. Ultra small (L=20 nm, W=20nm) CMOS transistors behave a single elecrone quantum dot, when operate at cryogenic temperature. ii- Electrochemical Assembly:- Highly ordered arrays of quantum dot may also be self assembled by electrochemical techniques, Atemplate is created by causing an ionic reaction at electrolyte metal interface Which result in the spontaneous assembly of nanostructures. Characterization Quantum dot can be characterized by two techniques: ii- Optical Characterization Electron microscopes and atonic force microscopes (AFM) are widely used for the optical characterization of the size of the qdots. For the cross section investigation of pdote structures, transmission electron microscopy (TEM) is the moste used Ii- Electrochemical Characterization: Qdots can be detected directly or indirectly by oxidatively dissolving the metal ion into aqueous metal ion and then electrochemically sensing the ions by using stripping voltammetry or potentiometry or electrochemical impedance spectroscopy (EIS) Conclusion (Discussion) Quantum dot can be synthesized to be essentially any size, and therefore, produce essentially any wavelength of light. The future looks bright and exiting on all the possible applications of Quantum dot. Quantum dote is Nano crystal made of semiconductor material that are small enough to exhibit quantum mechanical properties. There are several ways to confine in semiconductors resulting in different methods to produce quantum dot. Quantum dot formed when electron goes up in ground state to existed state after that this electron goes down to the ground state after extinction of light (energy) so in the location of electrons drop behind of spot or dot (hole) those hole are Quantum dots.