Author Topic: Molecular Layer Electrodeposition of Semiconductors  (Read 2320 times)

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iFred

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Molecular Layer Electrodeposition of Semiconductors
« on: September 07, 2004, 10:56:38 PM »


Molecular Layer Electrodeposition of Semiconductors

Compound semiconductor films are commonly synthesized by

molecular beam epitaxy, chemical vapor deposition, or vapor phase

epitaxy in the fabrication of optoelectronic devices. To date, stringent

material quality requirements have excluded electrodeposition

for synthesis of semiconductor compounds for this application.

In a recent report, Shalini Menezes of InterPhases Research in

California described a novel electrochemical deposition scheme for

preparing molecular layer structures of semiconductor materials.


The successive electrodeposition of monolayers of the compound

was performed from a single electrolyte containing all of the constituent

elements. Menezes showed that controlling the kinetics of

the competing reactions by careful regulation of temperature, electrolyte

composition, deposition potential, solution volume, and

anodic dissolution potential is critical to producing a film of the

desired stoichiometry. The author demonstrated the versatility and

unique features of this method, known as molecular layer electrodeposition

(MLE), by growing CuInSe2 films that are commercially

important in solar cell applications.


In other words "electrochemical deposition!!"


Link about semiconductor making...

http://www.tpub.com/neets/book7/24f.htm


Doping materials

http://inventors.about.com/library/inventors/blsolar5.htm


Using organic Semiconductors and Conductors

http://www.tda.com/eMatls/ntype.htm


VERY COOL! I never really thought about it but, lets just say that you start with a peice of metal, place it into a chemical bath of some dilluited chemical that produces a postive layer like a solution containg "boron" and a negitive solution "phosphorous" in two different beakers, apply charge to the plate and more or less produce a cell after dipping and creating the electrochemical deposition that is required. It would be cheap and fast to produce, even if it had impuritys and was less then say 7% efficient or so...


What do you think?

« Last Edit: September 07, 2004, 10:56:38 PM by (unknown) »

Norm

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Cheap vs efficient
« Reply #1 on: September 08, 2004, 08:09:42 AM »
 Cheap and efficient...you have to admire some peoples thinking. For example I read where they were trying to make solar cells as efficient as possible...then someone asked the question Why not make them cheaper even 70% if it were to cost only half as much as the 95% ones?

 If some of us wanted a flywheel we would take an old truck tire and do the best we could with it while technology was trying to make a superflywheel that spins at mega-rpms and gives you 500 miles per charge.

                   it's all fun 'tho...

                 ( :>) Norm  
« Last Edit: September 08, 2004, 08:09:42 AM by Norm »

Chagrin

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Re: Cheap vs efficient
« Reply #2 on: September 08, 2004, 08:22:09 AM »
Would 25 kWh get you 500 miles?


http://www.beaconpower.com/products/EnergyStorageSystems/SmartEnergy25kWh.htm


Would love to see some of the engineering in these things.

« Last Edit: September 08, 2004, 08:22:09 AM by Chagrin »

jacquesm

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Re: Cheap vs efficient
« Reply #3 on: September 08, 2004, 08:33:14 AM »
Nope, not even close... a car once accelerated needs a good bit of power just to keep cruising, 20...30KW in the smallest of vehicles. so 25KWh will give you (assuming 100% conversion, which is a pipe dream) no more than 100 Miles, and probably way less than that.
« Last Edit: September 08, 2004, 08:33:14 AM by jacquesm »

jacquesm

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Re: Cheap vs efficient
« Reply #4 on: September 08, 2004, 08:42:21 AM »
bad form to respond to my own post, but let me clarify that a bit. I am assuming that you are never going to move more than 100 mph in any vehicle, and if that takes at least 20..30 KWh  then that places an upper limit on the amount of distance you can cover with that energy.


Energy storage systems using flywheels have been used in transportation devices (most notably a couple of buses and a prototype developed by American Flywheels Inc), but without a whole lot of success.


The big key in developing a flywheel based storage system is the 'self discharge' based on drag and friction (air around the wheel and bearings). The first can be combatted by using an evacuuated chamber, the second by using magnetic bearings.


There has been some progress in this field, a static (no control mechanism) magnetic bearing has been designed, tested and subsequently patented using a rotating halbach array with compensation windings.


The biggest use for flywheel based storage systems right now is in 'ridethrough' applications for hospitals and other places that need 100% reliable power. You realy don't want the lights to go off while you're on the operating table :)


These systems typically are in the 10...100 KWh range, but are designed to liberate that in the few seconds that it takes to fire up the diesel and take over from the failed grid. The KWh rating is misleading, it suggests that you can draw that power out over a longer period of time, but really you usually can not, the self discharge rate (usually a few % per minute of operation) gets in the way of that.

« Last Edit: September 08, 2004, 08:42:21 AM by jacquesm »

Ungrounded Lightning Rod

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Re: Cheap vs efficient
« Reply #5 on: September 08, 2004, 09:56:35 AM »
25 kWh would be about 18 HP Hr, and would let a small car cruise on the level for about an hour - though it wouldn't get it up to speed.


But I bet that flywheel system is:

 a) Too heavy, and

 b) doesn't have bearings suitable for use in a vehicle (being designed for stationary use).


Having your car blow up if you hit a bump is a bummer.

« Last Edit: September 08, 2004, 09:56:35 AM by Ungrounded Lightning Rod »

TomW

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Re: Cheap vs efficient
« Reply #6 on: September 08, 2004, 10:56:51 AM »


Lets not forget / overlook the gyroscopic effect of a flywheel on such mundane things as cornering, large dips and collisions ;=>


T

« Last Edit: September 08, 2004, 10:56:51 AM by TomW »

juiced

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Re: Cheap vs efficient
« Reply #7 on: January 12, 2005, 11:06:07 PM »
Ive actually read that a car, once at the desired speed requires relevantly little power, as low as 5 HP to keep its momentum. A hill will bring it up to some 75% of full HP use and acceleration on a hill with all electrical systems on, 97% or so. No links off hand though.
« Last Edit: January 12, 2005, 11:06:07 PM by juiced »