5/3 Blog Post 2

On Tuesday, our Nanoscience class had the opportunity to tour the University of Kentucky's Advanced Science and Technology Commercialization Center where they specialize in certain nanotechnologies including nano-scribes and photolithography. I was super excited about this trip; I have an older brother who graduated from the UK College of Engineering, and he had told me about some of the interesting equipment and research that the ASteCC does. So, it was very interesting to see some of the equipment in real life finally. Our tour included four different stops: electron beam lithography, photonics, the clean room, and an atomic force microscope. 

Stop 1: Our first stop was to the basement of the center where a graduate student showed us electron beam lithography. This device uses a reverse electron beam microscope which has a patterned generator, allowing a stream of electrons to be emitted in specific patterns. An electron beam lithographer works similarly to a nano-scribe, which I will talk about later, as they both produce a 3D etching into a surface of the substrate. During my group's rotation, the graduate student could not get the electron beam lithographer to work so we unfortunately did not get to see the device in action. However, we did discuss research projects that expose the polystyrene with a higher dose of electrons, causing them to become fluorescent. 

F. 1 Shown here is the electron beam lithographer opened, ready 

                                          to accept a sample substrate to shine beams onto!

Stop Two: Our second stop of the trip was to the photonics department. Electronics uses electrons, while photonics uses photons or particles of light. This is considered the future of technology, as there have not been many advancements in electronics recently. Moore's Law defines the historic exponential growth of electronics — every few years the density of chips increases by 10x. However, there comes a limit at how dense you can make a chip since we are now referring to things on the atomic scale. Therefore, in order to have more advancements, we will have to stray away from electronics and into something different: photonics. While one can technically make electrons faster than the speed of light, there are many difficulties as one would then have to add capacitance in order to slow down the electrons. Additionally, electronics is a binary system, relying on 1s and 0s in order to convey information. While photonics can carry binary information, we can also adjust the frequency, amplitude, wavelength, etc. of the photon in order to convey different information. Photonics is not just on the x, y, z grid, it also has rho, pitch, and yaw which allows for even more specificity to convey minute details. Using photonics, researchers are developing neural networks which are designed to mimic brain processing and capabilities. The neural networks have endless applications, most interesting are the healthcare applications. With the COVID-19 pandemic, there were several issues with testing as far as accuracy, efficiency, and accessibility. With neural networks, a photonics chip could be sent out with a battery powered photon source that would test for the presence of COVID-19. The graduate student in the photonics lab pointed out that the labs that were preparing these photonics chips liked to say that they could have billions of units ship out $1 per unit. In house, the graduate student was working on passive wave guides which are made up of silicon and allow for total internal refraction -- the photons cannot travel in a straight line, they must be refracted. A lot of the processing computers tended to be older systems which was odd for the complexity and novelty of the photonics being produced. 

F. 2 Shown here is the wave guide set up which is also connected to a

microscope allowing the researcher to see what they are doing at 

such a small scale. 

Stop Three: Our third stop of the tour was to the Clean Room which is where we got to see the nano scribe in action. The clean room requires visitors to "scrub up". While this did not make sense at the beginning, the guide explained to us that since we are working on a nanometer level, a speck of dust would be massive in comparison to what was being built and worked with. The guide mentioned that in a real clean room, deodorant, makeup, perfume, etc. is forbidden. Again, those particles are much bigger than the substrate particles. This room was yellow in color. The lack of white light prevents pre-exposure of the photoresist. The nano scribe narrows the beam of light and makes monomers into polymers on a 3D level. The center of the beam is the most concentrated, which is the only part of the beam that is strong enough to do so. The nano-scribe is actual 3D printing at a nanoscale, whereas photolithography, which we also discussed, is 2D. Photolithography is a big flash lamp that shines through a mask that cures certain areas of monomers to a polymer. It uses a template to instantly make designs (a nano scribe is much slower). This device can also do a much larger area much quicker than the nano-scribe can. Because of this, photolithography makes all semiconductors, so it is an incredibly important device. While this device has an immense impact with technology, it also has healthcare applications as it can be used to create cell scaffolding. Cell scaffoldings can be used to form new tissues for a specific purpose by intentionally causing different intercellular interactions. The guide also mentioned a potential use of creating a tool that could separate blood components. This would be incredibly helpful for healthcare in transfusions and donating blood. He was also able to nano scribe our Transy bat logo which was very interesting to watch!

F. 3 Unfortunately, since this was a clean room, no pictures could be taken in the actual room

of the equipment. However, here is a picture of us before going into the clean room. We had to

put on a suit -- similar to the lab coats we have to wear in the microbiology labs,

shoe covers, a mask, gloves and a hairnet. This prevents particles from interrupting and 

compromising the nano-system.

Stop Four: Our fourth and final stop was to the atomic force microscope room, which was my favorite stop. The atomic force microscope (AFM) is an incredibly sharp needle; it is atomically sharp. This needle is called the cantilever. Old AFMs used to compromise the sample more commonly as the previous devices used to require actual contact with the sample. This was incredibly unfortunate for biological samples as they are much softer samples. Fortunately, new AFMs rely on Van der Waals forces which do not require actual contact with the sample. Instead of touching the sample, it is more of a "tap", having different settings of the degree of severity of the tap. Touching the sample directly was also problematic as the needle could easily get dulled or contaminate other parts of the sample. AFMs do this to produce a map of the sample by recording the height that is measured. Perhaps more impressively, if a nano-scribe product had a small speck of dust on it, the AFM could be used to remove the dust without harming the rest of the product. The biological application of this device is insane -- it can be used to measure the force by distance of a protein, the AFM can unfold the protein. The second part of this room was a spectroscopic ellipsometer which measure the amount of coating on a nanoscale product. Usually with photolithography or nano-scribes, the products are coated with something in order to be used. However, the coating can only be so thick. Therefore, the spectroscopic ellipsometer plays with polarized light to determine the thickness of the coating. A white light lamp is shown on the product at an angle and polarized, the optical polarization is then measured and a thickness is calculated. The guide mentioned that this device is one of the most used devices they have: pretty much any product or device that is made is run through the ellipsometer. 

F. 4 This is the Atomic Force Microscope which was my favorite tool we saw!

The device itself is that middle part, the rest are just supports and stabilizers, plus a digital

microscope that shows what is being looked at. 

F. 5 This is spectroscopic ellipsometer. The white light lamp is on the left, and the sample 

is placed on the middle circular stage. The guide ran the ellipsometer and the measurements were

taken in under two minutes!

Overall, this trip was incredibly informative, and I am very glad I got to go!! I am sad that I do not get to go tomorrow to see the microscopes but very grateful that I got to see some of the devices that produce nanotechnology. This will be potentially useful with my internship this summer at a clinical trial company; if I get to interact with any nanotech clients, I will have at least some clue of how it was made.