l**********n
发帖数: 72 | 1 Any one could tell me what's the typical dot size? Is it around (500 nm)^3 or
even less? What's the separations between dots? What is the electron diffusion
length?
What are the growth techniques for semiconductor quantum dots? Normally what
are the materials? | Eg
发帖数: 80 | 2
That also depends --- but definitely not that many for the cases I know! It
seems you are considering a quantum dot as a 3D box (I saw in your original
post you said 500nm^3) --- that's a very wrong idea, the confine ment in Z
direction is very different with that of the XY surface. You'd better read
some introductory quantum dot book first.
That's a kinda easy idea but not that easy to realize. Just imagine, how do
you control the density --- most people use a frontgate. Then learn from the
in
【在 l**********n 的大作中提到】
: Any one could tell me what's the typical dot size? Is it around (500 nm)^3 or
: even less? What's the separations between dots? What is the electron diffusion
: length?
: What are the growth techniques for semiconductor quantum dots? Normally what
: are the materials?
| g**h
发帖数: 15 | 3 In self-assembly semiconductor quantum dots, the literal size is around
10~50 nm and height around 5~10 nm. But it's very difficult to measure
the exact dot size and shape experimentally. The areal dot density is
around 10^9 cm-2 to 10^11 cm-2, you can use this data to estimate the
average separation between different dots. I don't know electron diffusion
length, give me some clue.
The most common growth technique for QDs is the strain-driven self-
assembly technique. For example, the lattice co
【在 l**********n 的大作中提到】
: Any one could tell me what's the typical dot size? Is it around (500 nm)^3 or
: even less? What's the separations between dots? What is the electron diffusion
: length?
: What are the growth techniques for semiconductor quantum dots? Normally what
: are the materials?
| l**********n
发帖数: 72 | 4 That's great! Thank you for your information.
Actually my current interest is that it's possible to make InP or ZnO
nanotubes with around 50 nm in diameter and separation around 200 nm very
efficiently. If I grow the p-type nanotubes along x direction and then n-type
nanotubes along y direction, it's possible to obtain many LEDs on the grid
points with density about several tens per micron square. Since the
distribution of crossing points is highly organized, and electron transport
within the na
【在 g**h 的大作中提到】
: In self-assembly semiconductor quantum dots, the literal size is around
: 10~50 nm and height around 5~10 nm. But it's very difficult to measure
: the exact dot size and shape experimentally. The areal dot density is
: around 10^9 cm-2 to 10^11 cm-2, you can use this data to estimate the
: average separation between different dots. I don't know electron diffusion
: length, give me some clue.
: The most common growth technique for QDs is the strain-driven self-
: assembly technique. For example, the lattice co
| c*s
发帖数: 2145 | 5 for fabrication of a 2 dimensional semiconductor nanotube grid, techniquelly,
it is not a big deal from a chemists's view point.
If interest, you can refer to Whitesides' work, in which pure crystals with
hundred nanometers can be patterned on a silicon chip.
If you want to know more about this, I can be a little helper. :)
n-type
between
fermi
has
heard
like
【在 l**********n 的大作中提到】
: That's great! Thank you for your information.
: Actually my current interest is that it's possible to make InP or ZnO
: nanotubes with around 50 nm in diameter and separation around 200 nm very
: efficiently. If I grow the p-type nanotubes along x direction and then n-type
: nanotubes along y direction, it's possible to obtain many LEDs on the grid
: points with density about several tens per micron square. Since the
: distribution of crossing points is highly organized, and electron transport
: within the na
| c*s
发帖数: 2145 | 6 sorry, I do not know how far you have step in this area ralative to
fabrication of pattern on wafer.
actually the fabrication is based on existing techniques as what I said
"technically not big deal"
SAM of line pattern first, with carboxyl group at end, adsorb stoichiometric
Zn and other ions onto it. Heating at higher temperature and conversion metal
ions into oxides.
repeat this process with only variation of the SAM direction.
this is combination of several ideas & papers
You can refer to J.
【在 l**********n 的大作中提到】
: That's great! Thank you for your information.
: Actually my current interest is that it's possible to make InP or ZnO
: nanotubes with around 50 nm in diameter and separation around 200 nm very
: efficiently. If I grow the p-type nanotubes along x direction and then n-type
: nanotubes along y direction, it's possible to obtain many LEDs on the grid
: points with density about several tens per micron square. Since the
: distribution of crossing points is highly organized, and electron transport
: within the na
| c*s
发帖数: 2145 | 7 I do not know if it will help or interest you.
first, ZnO is a direct band gap semiconductor, which is not suitable for LED.
Then when it comes to GaAs or other III-V SCs, the fabrication technique I
mentioned can not be deployed.(because the precursor for III-V is not
hydrophilic)
in the meantime, I believe the defects in the nanowire can be avoid, since,
you can see from some works of Aizenberg, the crystal is fair perfect. As I
think, the concentration of Zn and heating is key step in the sto
【在 l**********n 的大作中提到】
: That's great! Thank you for your information.
: Actually my current interest is that it's possible to make InP or ZnO
: nanotubes with around 50 nm in diameter and separation around 200 nm very
: efficiently. If I grow the p-type nanotubes along x direction and then n-type
: nanotubes along y direction, it's possible to obtain many LEDs on the grid
: points with density about several tens per micron square. Since the
: distribution of crossing points is highly organized, and electron transport
: within the na
| l**********n
发帖数: 72 | 8 It seems there are many research groups on LEDs, including polymer, and
semiconductors. What's the quantum efficiency of these LEDs? What's the
world's best record?
I am familiar with Yang's paper and group. The theory is still not clear. He
chose the proper material and it will be quite amazing if he grows InP
nanowires with the same alignment.
Remember to read my post on human retina. Tell me what you think.
most
stoichiometric
give
the
LEDs,
I
【在 c*s 的大作中提到】
: I do not know if it will help or interest you.
: first, ZnO is a direct band gap semiconductor, which is not suitable for LED.
: Then when it comes to GaAs or other III-V SCs, the fabrication technique I
: mentioned can not be deployed.(because the precursor for III-V is not
: hydrophilic)
: in the meantime, I believe the defects in the nanowire can be avoid, since,
: you can see from some works of Aizenberg, the crystal is fair perfect. As I
: think, the concentration of Zn and heating is key step in the sto
| t*****s
发帖数: 1240 | 9 commercial LED efficiency 20%(lambda=P/IV)
commercial LEDs always acheived best efficiency
in this area, Japan scientist rules, like Shuji Nakamura, a legend though.
Yang Peidong's work on GaN nanowire is amazing, but I dont expect too much
for GaN sythesized from quartz tube, that kind of purity is definitely not
suitable for LED or LD application.
of course You would be surprised at Yang's GaN nanowires with excellent
allignment, but I would say , that's normal if you look back at the history
【在 l**********n 的大作中提到】
: It seems there are many research groups on LEDs, including polymer, and
: semiconductors. What's the quantum efficiency of these LEDs? What's the
: world's best record?
: I am familiar with Yang's paper and group. The theory is still not clear. He
: chose the proper material and it will be quite amazing if he grows InP
: nanowires with the same alignment.
: Remember to read my post on human retina. Tell me what you think.
:
: most
: stoichiometric
| t*****s
发帖数: 1240 | 10 LED RGB(red green blue) will be used to take the place of traditional
vacuum bulb since LEDs' lifetime is much longer and wont die suddently.US will
replace the traffic signal light with LEDs in the future, just think about
how many traffic signal light are there. |
|
