• My scanning tunneling microscopy experiment.
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Hey boys and girls. I'm currently studying physics BA and we finally arrived in a stage where we are allowed to do more interesting experiments besides running a Stirling motor(although stirling motors are awesome) I thought I'd show you guys what we are doing and some nice pictures we got out of it! Because I don't want to explain the whole scientific mumbo-jumbo, here is a Wiki-Link: [url]http://en.wikipedia.org/wiki/Scanning_tunneling_microscope[/url] [b]What you need to know:[/b] The STM was one of the first devices that allows us to gather some image-information of matter in atomic scale without working in the k-room(basically the impulse-vector of light instead of the space-vector). Here is a nice little wiki-image of what is happening: [img]http://upload.wikimedia.org/wikipedia/commons/thumb/f/f9/ScanningTunnelingMicroscope_schematic.png/400px-ScanningTunnelingMicroscope_schematic.png[/img] [u][b]My STM Experiment so far![/b][/u] [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/DSCF2243.JPG[/img_thumb] Here you are seeing the devices we are using. The thing on top is an electronic microscope and belwow it is the pretty modern STM. The black thing at the left is the control unit and the grey thing is just two fancy lamps. Here is what it looks like up close: [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/V36_2010.jpg[/img_thumb] (image taken by my professor) It's sitting on a plate of granite or something which itself rests on a blown up inner tube of a bike-wheel. It's built like that so no stupid vibrations from people walking around, the building+wind and the tram driving nearby are destroying our pictures. Here is a pic I took myself: [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/DSCF2244.JPG[/img_thumb] And here is what the electronic microscope gave us at the PC, an image of the tip so we know when we are close enough: [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/TunnelSpitze.bmp[/img_thumb] On the left is our prepared probe of graphite, on the right the tip itself. Believe it or not, the tip is actually not touching the probe! And also nice: You can see the reflection of the tip on the graphite. This implies that we found a nice smooth surface of the probe that would otherwise not reflect that much when observed with the unarmed eye. However, the first probe we took was a small plate of [b]GOLD![/b] And here are some pics! [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/gb1.png[/img_thumb] The gold upclose! See the conglomerates? Awesome, isn't it? Look at the scale! [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/gb3.png[/img_thumb] Same point, turned 90 degrees! [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/Gold-Bild2.png[/img_thumb] Our clumsy professor touched the device so we had to take a different point. [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/gb6.png[/img_thumb] This is the gold more upclose. You can't see the atoms because metals have electron-clouds and the experiment uses electrons, so what we see is rahter the density function of the electrons than the atoms themselves! [b]Next up was graphite![/b] [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/sb1.png[/img_thumb] Got a good spot! You can already see the gaps between the single layers of carbon that graphite is actually made of! [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/sb2.png[/img_thumb] Can you guess where we zoomed in? [img_thumb]http://dl.dropbox.com/u/3046933/Fpraktikum/Tunnelmikro/Preu%C3%9F%20Riedel/sb7.png[/img_thumb] Hooray! Hexagons! C-Atoms! Only took us 4 hours because our professor crashed the needle into the probe twice so we had to make 2 new ones! I hope you enjoyed this quick excursion. Sure I made some mistakes, critics are welcome but even more welcome are questions as I only can learn from it!
Does the BA stand for Bad-Ass? Cause this is!
Bachelor :D I'm afraid my thread can go to hell in comparison to Hexxeh's NY times greatness :(
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