By: Christopher Shing October 7, 2010 Microscopes at RPI By: Christopher Shing October 7, 2010 Hi everyone. Since we’re doing the microscope lab today I thought I’d talk a little bit about how we use microscopes at RPI.

What are some examples of microscopes? What is a microscope? An instrument that makes small objects look larger. What are some examples of microscopes? Compound microscope, Transmission Electron Microscope, Scanning Electron Microscope, Scanning Tunneling Microscope. So, what is a microscope? Who can tell me? (Have kid answer question). That’s right, a microscope is an instrument that makes small objects look larger. Now, what are some examples of microscopes? (Ask a few kids). That’s right, there are compound microscopes, transmission microscopes, scanning electron microscopes, and scanning tunneling microscopes. Today you guys will use a compound microscope.

The Compound Microscope Uses several convex lens to magnify an object by bending the light that passes or reflects through it. I use it at RPI to help when testing semiconductor devices. Now, even at RPI we use compound microscopes to do our tests. A compound microscope works using several lenses to magnfiy an object by bending the light that passes through it or reflects off it. Here you see I am using a compound microscope to help me test a device our lab has made. Now on this device we 25 sets of electrical contacts that are so small, on the order of 100s of micrometers. Now a micrometer is, by drawing out the rest of our metric staircase, 6 steps down from the base unit. That is 1,000,000 times smaller than a meter. So I use the microscope to magnify the surface so that I can touch the metal contacts with two needles. This way I can get the data I need from it.

The Scanning Electron Microscope High resolution microscope that can magnify an object up to 150,000 times. Uses an electron beam to observe an image. Located in the RPI clean room. There are also more advanced microscopes that I use to allow me to understand the devices our lab makes. For example, our group uses a Scanning Electron Microscope to allow us to magnify an image up to a 150,000 times its actual size. In this picture we can see the inside of an electron microscope. What will happen is we will put the sample to be tested inside of this vacuum chamber. A large voltage is applied such that electrons are accelerated and driven towards our sample. The electrons then bounce off of our sample and then collected above. The electrons are then counted and an image is formed. This second picture is of my coworker. This last picture is me using the SEM.

SEM Images So, I’ll pass two things around and show you a few images. The first is a container of Zinc-oxide nanoparticles. Do not open this. Our group works with this material to collect ultraviolet light. What my coworker or I will do is deposit this material onto another material, such as a quartz slide, and then measure some of its optical properties. The second one such device. This is a ZnO nanoparticle ultraviolet photodetector on quartz with gold contacts. You can see how small these contacts are and why I need a microscope. Now, does anyone know how small nanoparticles are? (Wait). Nanoparticles, on our metric staircase, are nine steps from the base unit. That means it is 1,000,000,000 times smaller than a meter. Now, using the SEM I can get pictures of these nanoparticles to understand more about them. In the bottom left I have a false-colored picture of the ZnO nanoparticles next to a gold contact. That is on the order of 10 micrometers, or 100,000 times smaller than a meter. The picture on your left is the nanoparticles. You can see from the scale that these particles are 100s of nanometers big. Now that is very small.

Smart Applications: USB Microscope A small camera and several lenses magnify an image. Uses LEDs to increase the illumination. Works similar to a compound microscope. Have fun! Well, I brought in a USB microscope that a professor at my school owns. This is a demonstration of a Smart Application. Now, who can tell me what does Smart Technology mean? (Wait.) Smart Technology is all about technology with a brain. For example, how would you like it if you were watching TV and the TV only put on shows you liked to watch? Or how about, what if when it got dark your house would automatically turn on the lights? And not only did it turn on the lights automatically, it helped your parents save on their energy bills by calculating the proper amount of light needed in every room of your house? Wouldn’t you like that? Well, what I’m going to show you guys and let you have some fun with after you finish your activity is a smart microscope. This microscope works by it has a small camera and several lenses and zoom feature that allow it to make small images bigger. For example, who can tell me how many Lincoln’s are on a penny? Or what does the screen of your cell phone look like? The microscope is smart because it’s LEDs automatically adjust the amount of light needed to illuminate the image. That way, you don’t have to spend time trying to illuminate the image in the right direction. This works similarly to a compound microscope. Ok, now work on your activity. If you finish early you’ll get to try this out. See what things you can magnify!