These past few weeks were a bit busy, I had a lot of stuff from school. I went to a few hackathons, and I worked on the Autonomous car project, but I haven’t made much progress. I am currently working on an app for the PCR Project, so you can control it wirelessly, but you won’t hear from that for a few more weeks. But recently, I received an Arduino MKR1000 from the Hackster.io World’s Largest Arduino contest. So now I have to make a project. This time, I will make a Scanning Tunneling Microscope.
What is a Scanning Tunneling Microscope?
A scanning tunneling microscope is a type of microscope that can “feel” atoms. Normally, when one needs to view a specimen that is fairly small, you would use a light microscope. But when the specimen is so small that it is smaller than the wavelength of visible light, then one would look into other types of microscopes that do not use light to magnify/visualize your specimen. There are many different types of these microscopes. The electron microscope and the atomic force microscope(AFM) are the most widely used. Electron microscopes use electrons instead of photons(light) to view specimens, but they only work when the specimen is either electrically conductive or coated with a conductive substrate(spray). The other type, the AFM, “feels” atoms instead of “seeing” them. The type I will use is a scanning tunneling microscope. In theory, when electrical current is applied to two different objects, and they are moved close enough, electrons can “jump” between the objects. This “jumping” of the electrons is called quantum tunneling. We can use quantum tunneling to “feel” these atoms in a scanning electron microscope. In the microscope, a needle with a very fine point(one atom) is used to scan a specimen, and based on the different voltages produced by the tunneled electrons, we can construct an image of the atomic structure of the specimens.
How will I make it?
In normal scanning tunneling microscopes, a piezo tube or a piezo stack is used to move the scanner tip. I will try to use a piezo buzzer, like the one used in Alexander’s project(RIP Geocities). In his project though, he used an oscilloscope to view a very basic image. I intend to use the MKR1000 to receive and process the data for the STM, and then stream it online so the image can be constructed in probably a simple processing sketch. Since the current that gets tunneled is very low, a preamp and a separate opamp will be needed. I also need some serious vibration isolation and try to keep noise as low as possible. If I can keep noise and vibration low, the microscope is presumed to be able to achieve atomic resolution.