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Daniel Terry

Nanotechnology how does it come together?

How does a nanostructure come together? What materials and what instruments are used in order to make this happen?

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    Anonymous

    Hello,


    There are many methods to produce artificial or custom nanostructures, this in general depends on: 1. Type of Material desired (e.g. nanoparticle, nanowire or a quantum dot) 2. Desired property of the structure (e.g. size, uniformity, surface roughness) 3. The number of structures/particles needed


    If I’m not mistaken, what you like to know is concerning both nanomaterials and nanostructures.

    Nanomaterials: They often refer to Nanoparticles, which are produced by various methods. This process is often referred to as Growth/Synthesis. I can not elaborate much on this, as it is more related to Materials Science/Chemistry. Nanoparticles can be embedded within Nanostructures (e.g. Metallic Nanoparticles in Solar Cell, to benefit from the Plasmonic enhancement to effectively absorb more light). Carbon Nanotubes are also included within this category.

    Widely used materials in this category: Gold Nanoparticles and others.

    NanoStructures: They refer to patterned structures made with various techniques often to produce semiconductor devices (or so called sub-micron electronics = nanoelectronics). The methods used here are:

    1.Pattering/Lithographic Methods: Basically you have a base layer of some material, then you put a ‘light’ sensitive photoresist on then, with the help of a light source you can draw the structure you like on the base layer and then get rid of the photoresist. You can grow different materials this way and its a repeatable process. The limitation for the choice of growing different materials is the spacing between the atoms of different materials, as it has to be as small as possible (this is called the material crystal lattice constant).


    Widely used materials: GaAs, AlGaAs, Si, GaN and many others.

    2.Nano-Molds/Embossing:

    Basically you make a mold and you put it on top of some base layer to “stamp” that layer with the structure. It is not so widely used for industrial applications as it introduces some defects/dirt in the structure which can be very bad to electronics/optoelectronics, plus its a slow process. The patterning method is very fast. It is used for specific applications that are not highly sensitive to defects like Organic LEDs.

    3.Self-Assembly:

    I mentioned earlier the lattice constant. Certain materials when grown on top of others, can deform resulting in many bubble/islands like structures on the top, those are known as Quantum Dots. Molecular Beam Epitaxy allows atomic layer by atomic layer growth of the quantum dots , the dots are of high quality (i.e. low defects) making them useful for optical applications e.g. lasers.

    For methods and instruments used, it will be tedious to cover them, hence the following are keywords which you can look up on your favorite search engine and/or NanoHub:

    Fabrication Methods/steps/tools: CVD, PVD, MOCVD, MBE, Plasma Etching, Electron Beam Lithography, FIB (focused ion beam Characterization/Probing tools: STM, AFM, MFM, SEM


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  2. 0 Like 0 Dislike

    Mohanad Zaki

    Hello,


    There are many methods to produce artificial or custom nanostructures, this in general depends on: 1. Type of Material desired (e.g. nanoparticle, nanowire or a quantum dot) 2. Desired property of the structure (e.g. size, uniformity, surface roughness) 3. The number of structures/particles needed


    If I’m not mistaken, what you like to know is concerning both nanomaterials and nanostructures.


    Nanomaterials: They often refer to Nanoparticles, which are produced by various methods. This process is often referred to as Growth/Synthesis.

    I can not elaborate much on this, as it is more related to Materials Science/Chemistry.

    Nanoparticles can be embedded within Nanostructures (e.g. Metallic Nanoparticles in Solar Cell, to benefit from the Plasmonic enhancement to effectively absorb more light).

    Carbon Nanotubes are also included within this category. Widely used materials in this category: Gold Nanoparticles and others.

    NanoStructures: They refer to patterned structures made with various techniques often to produce semiconductor devices (or so called sub-micron electronics = nanoelectronics). The methods used here are:

    1.Pattering/Lithographic Methods: asically you have a base layer of some material, then you put a ‘light’ sensitive photoresist on then, with the help of a light source you can draw the structure you like on the base layer and then get rid of the photoresist. You can grow different materials this way and its a repeatable process. The limitation for the choice of growing different materials is the spacing between the atoms of different materials, as it has to be as small as possible (this is called the material crystal lattice constant).


    Widely used materials: GaAs, AlGaAs, Si, GaN and many others.


    2.Nano-Molds/Embossing:


    asically you make a mold and you put it on top of some base layer to “stamp” that layer with the structure. It is not so widely used for industrial applications as it introduces some defects/dirt in the structure which can be very bad to electronics/optoelectronics, plus its a slow process. The patterning method is very fast. It is used for specific applications that are not highly sensitive to defects like Organic LEDs.


    3.Self-Assembly: mentioned earlier the lattice constant. Certain materials when grown on top of others, can deform resulting in many bubble/islands like structures on the top, those are known as Quantum Dots. Molecular Beam Epitaxy allows atomic layer by atomic layer growth of the quantum dots , the dots are of high quality (i.e. low defects) making them useful for optical applications e.g. lasers.


    or methods and instruments used, it will be tedious to cover them, hence the following are keywords which you can look up on your favorite search engine and/or NanoHub: Fabrication Methods/steps/tools: CVD, PVD, MOCVD, MBE, Plasma Etching, Electron Beam Lithography, FIB (focused ion beam Characterization/Probing tools: STM, AFM, MFM, SEM

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