The study of the performance of ultra-small structures, materials, and devices, usu. usually 0.1 to 100 nm; also, the study of manipulating materials on an atomic or molecular scale. Nanoscience is sometimes used interchangably with Nanotechnology, which is the manipulation of matter on an atomic ...

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2k views

Perpetual motion machine of the second kind possible in nano technology?

First of all sorry for my English - it is not my native language. During my engineering studies at the university the thermodynamics professor told us that the "second law of thermodynamics is not ...
8
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0answers
360 views

Measurement of Tangential Momentum Accomodation?

(this question is a crosspost from theoretical physics.) I am using atomic force microscopy (AFM) for characterizing pores of the size of nanometers for application in gas flow. For this, knowing ...
7
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2answers
109 views

Is light red shifted in optical tweezers?

This is a question I put to my supervisor during my PhD many years ago, and never really got a satisfactory answer to. In an optical tweezers, assume that a beam of light is used to move a glass ...
6
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5answers
963 views

Nano-particle or Molecule?

What's the difference between something being labeled a "nano-particle" or it being called a "molecule"?
5
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2answers
486 views

How to determine the (n,m) dimensions of a carbon nanotube?

I've been reading about nanotubes lately, and I keep seeing the $ (n,m) $ notation. How does this describe a nanotube's structure? How do I determine which is $n$ and which is $m$ ? I'm familiar with ...
5
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1answer
273 views

Clarification of Landauer approach

I am trying to understand the Landauer approach. Consider the setup: (left contact)-(conductor)-(right contact). For simplicity, the conductor is a 1d wire (the transverse part is not relevant for ...
5
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1answer
425 views

How do High Electron Mobility Transistors (HEMT) work?

I am studying High Electron Mobility Transistors (HEMT), but I simply cannot understand how they work in the way described by the references I've read on the Internet. This is what I understand so ...
4
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2answers
1k views

If you had two “perfectly” flat surfaces of the same material?

Let's say you had 2 nano-engineered surfaces of diamond which were as 'flat' as possible (of course considering the radii of each carbon atom in the lattice)... would there be any friction between ...
4
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3answers
690 views

Nanorobots. What stops us from producing them yet?

If we can already predicts accuratelly motion on molecular levels, what stops us from developing small robots to, for instance, navigate through our blood vessels looking for cancerous cells and ...
4
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3answers
143 views

Why can we quantize macro(meso)scopic harmonic oscillator?

It is well known that we have got many kinds of quantized macro(meso)scopic harmonic oscillators or so in tiny mechanical systems. People are talking about cavity cooling and so on. However, it is ...
4
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1answer
392 views

Fourier transformation, electric field and magnetic field to have a shielding lattice against particles

With Fourier-Series Expansion, we can write a function as sum of many non-repating different frequncied different amplituded sine and cosine functions. Lets assume we know electric-field and ...
3
votes
2answers
74 views

Can there be a string so thin as to be invisible, but that can still support a visible weight?

A spider web thread is very thin, yet it can support a spider. Given that the human eye visual acuity is finite, are there materials, natural or man-made, sufficiently thin that a string made from ...
3
votes
1answer
639 views

Nanotube chiral angle as a function of $n$ and $m$

I'm looking into nanotubes and I thought I'd assure myself that the basic geometry equations are indeed correct. No problems for the radius, I quickly found the known formula: $$R = ...
3
votes
2answers
435 views

Nanotechnologies: current problems and general limitations

I have some questions about Nanotechnologies. I'm not physicist and my knowledges about the topic are limited by the "Engines of Creation" book by Eric Drexler. So I think that my questions are ...
3
votes
1answer
95 views

Specific Heat of Nano Particles

Specific heat of nano particles is less than bulk specific heat of them. Why?
3
votes
2answers
225 views

Layman's method to sharpen a wire (STM-tip)

We use a platinum-irididum wire to fabricate our STM tips. And by "fabricate" I mean to cut it with really sharp pliers or scissors. Sometimes we get good tips but most of the time they are not usable ...
3
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1answer
229 views

How are quantum potential wells fabricated?

Potential wells, such as infinite and finite potential well, have been the standard examples in quantum mechanics textbooks for tens of years. They started being only theoretical toy models but as ...
3
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1answer
104 views

Absorption/Extinction formula of nanoparticles

I know the absorption/extinction equations in nanoparticle physics should be: $$Q_{abs}=\frac{1}{2}\mathbf{Re}\int \mathbf{J}_{tot}\cdot\mathbf{E}_{tot}^\ast ...
2
votes
2answers
3k views

What is the approximate electrical conductivity $\sigma$ of graphene in S/m or S/cm?

I am trying to find an approximate value of the electrical conductivity $\sigma$ of graphene in units of S/m or S/cm. This table on Wikipedia gives $\sigma$ values for a variety of materials ...
2
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1answer
39 views

Having nano-scale holes in metal, possible today?

I am considering to design a gas filtering system that is based on the size of gas molecules. Basic idea is to flow mixed gas in a long pipe, and to allow CO2 to get of pipe through nano-size holes ...
2
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2answers
47 views

What is light localisation?

Reading about plasmonic nanoparticles I faced the term "localised light". How can one localise light? What are applications of it?
2
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1answer
60 views

Electric field inside a metal nanoparticle?

In localized surface plasmon resonance, the conduction electrons of a metal nanoparticle oscillate in tune with the frequency of the incident electromagnetic wave . The effect is dominated by ...
2
votes
1answer
940 views

Nanotech - zero dimensional fullerene

Not really a physics junkie, and I think this is a chemistry question, but since there's no chemistry.stackexchange.com (yet) I think here is the best place. I was just reading up on nanotech and ...
2
votes
1answer
74 views

One-dimensional (1D) CdSe nanostructures

I'm not a physicist, but I'm really interested in Nanotechnology. I've a question, and I hope that I can be provided by an answer. I was reading some articles about the one-dimensional CdSe ...
2
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0answers
31 views

Au, Ag nanoparticles plasmon peak position?

Is the interaction between metallic nanoparticles (~ 20 nm) and light in the UV-Vis-NIR range governed by Mie theory or by Rayleigh scattering theory? Where are the Au and Ag plasmonic peaks located? ...
2
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0answers
81 views

High Young's Modulus and Tensile Strength of Carbon Nanotubes

I was recently reading about Carbon Nanotubes having extremely high Young's moduli, as well as high Tensile Strength, making them very interesting fibers. However, when I read this I wondered what was ...
2
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0answers
233 views

How to calculate radiative transition rate of exciton in a quantum dot with specific dimension?

I am writing rate equations for a nanophotonic system including three quantum dots. I need to calculate that radiative transition rates of exciton in ground state in those quantum dots. In the paper ...
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1answer
512 views

Why is honeycomb lattice the ideal shape for solar cells?

Quoting this web site (which I haven't thoroughly verified for credibility yet): The material is graphene, also known as graphite, a naturally-occurring mineral that forms a one-atom-thick ...
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vote
1answer
2k views

What is the electrical conductivity (S/m) of a carbon nanotube?

I have been searching around for a while for this but I am having trouble finding any actual figures, all I can seem to find is that it is "very high". So I am wondering, does anyone have any figures ...
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4answers
217 views

Quantum dots on the nuclear scale!

Quantum dots are quantum systems that are confined by definition on the nano scale. Why didn't people study similar systems on a much smaller scale, something as small as the dimension of the nucleus? ...
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vote
1answer
77 views

Why are carbon nanotubes are so difficult to create?

I have heard that the future of the techonolgy are the carbon nanotubes due to their resistance and conductivity, but why are they so difficult to create?
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vote
2answers
192 views

Quantization of momentum in nanotubes

I'm reading about carbon nanotubes and how the momentum (lets call it $k_x$) is quantized along the circumferential direction and not along the cylindrical (call this $k_y$). I can follow the maths ...
1
vote
2answers
122 views

Light bending surfaces and energy funneling properties

In the last year there has been fuzz regarding metamaterials studied for the purpose of cloaking, and it seem to me they are somewhat glorified 2D waveguides, but in any case it seems a reasonable ...
1
vote
1answer
103 views

How to calculate the differential scattering cross section?

I am doing some simulations with the Meep code to study some properties of a metal nanoparticle. The situation is this: an incident electromagnetic wave on a metal nanoparticle. By now I know how to ...
1
vote
1answer
133 views

Electric Potential at nano scale

I’ve a got a question; and I am hopeful that you can provide any information or direct me to a better resource. I'm not a physicist; so please correct me if I'm wrong. Scanning Probe Microscopy (SPM) ...
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vote
1answer
414 views

gaussian fitting of xrd peaks

I am reading a paper regarding the nano crystalline material with hexagonal crystal structure. In that paper in order to find out lattice parameter of hexagonal crystal structure they have fitted a ...
1
vote
0answers
15 views

How come plasmon resonances of metals are capable of being tuned to different wavelengths?

I read in this article that plasmon resonances though being a pre-determined property of a metal are capable of being tuned to other wavelengths when these same metals are made into tiny ...
1
vote
1answer
28 views

Software for analysing SEM or TEM images

I am looking for a software to analyse SEM and TEM images of some PLD experiments because I want to characterize the samples, like calculate the concentration of nanoparticles, size, and do some ...
1
vote
0answers
43 views

Radius dependence of Energy levels of spherical Quantum dots

I have frequently read in articles that the energy level of spherical quantum dots depends on radius. We simply match the wave functions inside and outside the particle and find the intersection of ...
1
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0answers
50 views

Why does matter behave differently in the nanoscale? [closed]

I know that materials behave differently in the nanoscale. One of the reasons that I have heard as to why this happens is due to the increased surface area of the atoms. But, are there other factors? ...
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0answers
46 views

Ballistic Conduction - Difference between Bosonic and Fermionic Transport

Ballistic Conduction is the phenomenon of an ideal conduction environment for quantum particles - for electrons the Ballistic Conduction is not infinity, but is proportional to the difference between ...
1
vote
1answer
118 views

What is surface plasmon of metal nanoparticles?

I really want to understand about the Surface Plasmon of metal nanoparticles, if anyone can explain it to me i'll be grateful. I have checked Wikipedia for it but didn't get anything clear.
1
vote
1answer
181 views

What kind of phases nanoparticles have (gas-solid-liquid)?

If a phase transition requires a number of particles that is in the TD-limit, can nanoparticles (~10 atoms) have phase transitions? What kind of phases and transitions nanoparticles have?
0
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3answers
106 views

Is duplication of nucleus, electron and proton (sub-atomic particles) possible? [closed]

usually a single cell develops into a huge mass to form a substance or an organism. is this happening because of multiplication of sub-atomic particles? if yes, then is it possible to multiply the ...
0
votes
3answers
107 views

Do nanoscopes exist?

We are mostly all familiar with a microscope, and know that it helps to see MICRO components, like stuff that is photolithographically etched on silicon semiconductor die. (The latter can also be ...
0
votes
1answer
136 views

How long does it take to scan a typical scanning electron microscope image?

I suppose the answer depends on resolution and imaging area, but can you provide some ball park measures of imaging times with an SEM?
0
votes
1answer
127 views

Is phosphorene a topological insulator?

All of the other "-ene" materials (silicene, germanene, stanene, and even graphene) are topological insulators. Phosphorene and these other materials all have honeycomb lattices and would appear to ...
0
votes
1answer
161 views

Dopant Charge Transfer and Fermi Level shift

When a system has a dopant, how much does the Fermi level shift? For example, say a finite concentration of substitutional dopants replace some bulk atoms, and each has one extra electron. Ignore any ...
0
votes
0answers
17 views

What are the eigenstates of the sum of the exchange and hyperfine hamiltonian in a quantum dot?

I am trying to find the eigenstates for the Hamiltonian for a quantum dot (QD). Here, I am considering the exchange and hyperfine Hamiltonian. The Zeeman Hamiltonian is not included. $\hat{H}$ = ...
0
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0answers
27 views

Electron transmission in Landauer formalism: why just imaginary part?

In Landauer formalism the electron transmission function is defined as $T = Tr(G_M^\dagger\Gamma_LG_M\Gamma_R)$ where $G$ are Green's function of subsystems, index $L$ and $R$ means subsystem of ...