Tekforums
Chat => Photography => Topic started by: Mongoose on May 09, 2006, 23:57:44 PM
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I wonder if anyone can tell me what this is (I know of course)
except shakey, he is banned from answering
(http://img.photobucket.com/albums/v68/thatguypinchedmyname/STM.jpg)
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Yes, I see what it is.
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really? it looks pretty slick and well made but i got no idea what the hell it is lol
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an stm?
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Yes, I see what it is.
Yep, youre right! 8)
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lighter ?
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motor piston with laser guided aged gouda adapter.
Duh. :smack:
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PAC Man with a gun in his mouth?
:lol:
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well Maximus and Snellgroves suggestions are ammusing, but Deltazero is right
Its the benchtop STM (Scanning Tunnelling Microscope) which I am using for my final year project at uni.
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I win then?
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yeah a very low budget STM. I have the exact same one on my desk at work :)
Cutting the platinum wires is such a pain in the ass so I usually just go use the AFM across in chemistry and switch the heads over.
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yeah its pretty cheap for an STM, still better than the "digital microscope" which they presented me with for my 3rd year project though. Lets just say it had "Matel" stamped on the bottom! We gave up on it pretty quickly, just got an old optical microscope and clamped my Nikon Coolpix to the eyepiece, worked much better!
Yes Delta, you win, here are some of the forum cookies which I swiped when Serious wasnt looking
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yeah its a pretty useful bit of kit. You wouldnt publish anything using it but its great for quickly checking something or working out what the hell is going on with a surface. Managed to get the machine youre using down to atomic resolution on gold and pretty close to atomic on silicon so it can be done with careful tip preperation :). The only issue with that machine at those scales is the materials change so much with even a ray of light hitting them because theres no thermal regulation/ultra high vacuum.
What are you measuring by the way?
If you ever need a high end image/test doing just shout - got access to a lot of nice toys and no problem to book some time on them if its any use to you...
On a related theme, can you guess what this is?
(http://www.antarctic-one.com/images/DSC00019.jpg) (http://www.stevefishwick.co.uk/hidden/root/images/DSC00019.jpg)
Sorry taking with phone and no software to resize it on this machine...
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well thats deffinitly some sort of UHV setup, Id guess you have a rather more funky STM than mine in there? maybe some other toys as well but my experience in this area is pretty limited so far.
Were trying to image molecules at the solid/liquid interface. Basically trying to get hydrocarbons to adsorb onto the surface of graphite and then image them, its proving pretty challenging. Weve got pretty good atomic resolution on the graphite substrate but the hydrocarbons are proving elusive.
Im waiting on an answer from one of the profs at Nottingham to see if I can get onto a PhD in Nanoscience next year, so fingers crossed I might get to play with some more flashy toys in the future. Theyve got a very cool one here which has a transparent tip, allowing near field optical and STM at the same time with the same instrument.
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yeah a very low budget STM. I have the exact same one on my desk at work :)
What do you do, out of interest?
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On a related theme, can you guess what this is?
No, but something in me says "I want to have a play with that!"
:D
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Sorry taking with phone and no software to resize it on this machine...
Not even paint? :o
Anyways did a bit of editing for ya and now its clicky so the original is still available ;)
/studiously avoids nano nanoo jokes from mork and mindy
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Sorry taking with phone and no software to resize it on this machine...
Not even paint? :o
Anyways did a bit of editing for ya and now its clicky so the original is still available ;)
Cheers, nope not even paint at the time... I was using a small linux distribution attached to the machine in question and they get a little edgy about people installing software on the control machines. Could have fixed it since but forgot ;)
Its one of the small XPS machine with some STM stuff in there in one of the side bunkers at Daresbury synchrotron lab. The big metal cylinder at the back is the XPS giveaway in case you care.
What do you do, out of interest?
Research into molecular electronics and stoof. Surface science of semiconductors, dna wires, chip fabrication, whatever Im asked to play with really.
Were trying to image molecules at the solid/liquid interface. Basically trying to get hydrocarbons to adsorb onto the surface of graphite and then image them, its proving pretty challenging. Weve got pretty good atomic resolution on the graphite substrate but the hydrocarbons are proving elusive.
Yeah theyre going to be tricky to see.. If you can you could maybe view them in cross section with something like TEM (transmission electron). Contact/tapping mode AFM might be a slightly nicer alternative to STM if youre having problems as the equipment is pretty common in almost lab in the country.
Spreading the hydrocarbons Im guessing youre using a langmuir-blogett technique (dipping the graphite in a solution including hydrocarbons). Ive just put in an application this afternoon to buy a contact angle meter which is a really simple but powerful tool which looks at the angle a drop of liquid forms on the surface of a material. Its designed to measure exactly your type of layers and some similar things I work on. It may be able to help you determine the layer thicknesses and how perfect the layer is on your surface is if its any use to you.
Ive done some bits and bobs on physically bonding hydrocarbons (specifically 1-alkenes) to semiconductor/metal surfaces over the years which may be a nice route to look at if you get time as you can make them without much effort... The advantage of doing it that way is you get incredibly flat surfaces (compared to graphite) and you can prove the layers are there cheaply because the surface of the materials wont oxidise over time when you have a good layer, i.e. you can hydrogen terminate some silicon (111) in HF/NH4F (remove the oxide layer) then drop the chip in some 1-alkene chains and heat to about 160 degrees a layer forms. If you then use your STM tip to scan the hydrogen terminated silicon it will start out showing the step and terrace structure of the silicon but then degrade to an oxide layer over time. The alkyl monolayer one will stay looking like it was just raw silicon because the oxygen cant get to the surface. Its a really elegant experiment. :)
At the end of the day XPS is the best technique but its a pain in the ass to get beam time at any facilities. :( About the only good one you could use in this country is the one pictured above. Reflected FTIR (infrared absorbtion) would also work but Im struggling to find a lab that has a system that can do reflection measurements and actually has the machine operational at the moment but there is a PEM-IRRAS system up here Im trying to make them connect up which may also be useful to you?
If you have know idea what some of these tools are yet just ignore the above or ask your supervisor but Im happy to help you measure stuff if Nottingham doesnt have a particular machine (or more likely they do but have no postgrads/RAs free to help you test things)...
Would be interested to see what exactly youre working on as this field is a very small community and if youre thinking of PhDs theres a good chance wed end up working on stuff mutually beneficial further down the line. It never hurts to have a few more people/contacts you can bounce ideas off/share facilities :)
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Its one of the small XPS machine with some STM stuff in there in one of the side bunkers at Daresbury synchrotron lab. The big metal cylinder at the back is the XPS giveaway in case you care.
And heres me hoping its the labs new coffee machine :D
which is a really simple but powerful tool which looks at the angle a drop of liquid forms on the surface of a material.
Is there *anything* really simple anymore? It all seems bloody complicated to me :/
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Is there *anything* really simple anymore? It all seems bloody complicated to me :/
:( I tried to keep it simple but the silly people who came before me named everything really complicated names and abbreviations. Most things are really simple they just make it hard to get past the jargon.
In short, when water falls on a car bonnet it lays out into a big fat blob of water. When you wax your car the water beads up and sits on the surface as little pellet type drops. (like drops of dew)
(http://images.google.co.uk/images?q=tbn:wEUXoQ6K-v0gkM:upload.wikimedia.org/wikipedia/en/thumb/d/d3/Video_contact_angle.gif/300px-Video_contact_angle.gif)
a hydrophilic (loves water) surface gives big blobs of water with a small angle that want to stick to the surface.
(http://images.google.co.uk/images?q=tbn:1At_JEcWZyKIGM:www.brookes.ac.uk/other/jtrc/images/contact_angle.jpg)
a hydrophobic (hates water) surface makes the water stand up and try and run off the surface.
If you know what water looks like when its on the car paint only and also know what its like on pure wax then you can work out some clever stuff about the surface. If the water looks like it did on the car paint only then the layer is probably not there or its very thin. At the other end of the scale when the wax is thick enough it may as well be sat on solid wax. The shape of the drop will gradually change from one shape to another as the wax gets thicker or a better coverage. By seeing how much it has changed you can work out how well the wax is covering the surface, how thick it is, how pure it is etc etc just by taking a closeup photo of the water drop. Clever huh :)
(http://www.firsttenangstroms.com/faq/images/dropartt.jpg)
Now change the car for a chunk of graphite and change the wax for his chemical and it still works on a tiny scale. You can see whats on the surface or how clean it is just by looking at the water droplet and measuring the angle it touches the surface. Most other techniques involve scratching a hole in the material (destroying it) then trying to measure the tiny height change which may only be a couple of atoms high on this scale.
This just involves putting a drop of water on it and does the same :)
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and now weve entered my 3rd year project, which was measuring contact angles and rates of spread of hydrocarbon based oil drops on glass slides! we ended up using a rather heath robinson affair involving a nikon coolpix attached to the eyepiece of an old London Instruments microscope and a sodium lamp, it more or less worked though.
Thanks for the info and offers of help Steve, its much aprieciated. The droplets thing is particularly interesting as I had been wondering to myself if there was a way I could verify if the molecules Im looking for are actually there or not. The project I am doing atm is largely to do with investigating and demonstrating the capabilitys of STM under liquid as opposed to UHV or Air, so Im pretty much stuck with the equipment I have for now.
for now we are attempting to re-create the images achieved in
Self-Assembly at the Liquid/Solid Interface: STM Reveals
Steven De Feyter* and Frans C. De Schryver, J. Phys. Chem. B 2005, 109, 4290-4302
the molecule we have been using is one CH2 group shorter than their molecule A, but we are hoping to move on to some molecules which have been synthesised by the Nottingham Nanoscience group. If we can get it to work we should get to see things no one has seen before, but tbh I am a little sceptical that this scope is capable of the required imaging