As an undergraduate researcher I have become very familiar with using an atomic force microscope.  This amazing tool uses a very small device called a cantilever, which is basically a tiny record player needle made of silicon.  The machine taps the tip of this cantilever along the surface of the thing you’re trying to image and generates an image based on the interactions of the cantilever tip with the sample.  The movements of this cantilever are measured by bouncing a laser off the back of it and measuring how the deflection of the laser changes using a photodetector.  When the laser goes over a bump the laser will also move and a photodetector which collects this light records this change.

 Now most of the time the thing you’re trying to look at is already so smooth you cannot tell that there is any flaw by looking at it with your eyes, or sometimes even an optical microscope.  The atomic force microscope however is amazingly detailed and is able to draw an extremely detailed picture of what the surface if your sample looks like.

This image shows a 4 sided pyramid structure which grew as a result of a threading dislocation in a crystal I was growing.  The lines you see on this pyramid are actually atomic steps. Yes you read that correctly, they are layers which are a single atom thick. How’s that for high resolution?

I am consistently amazed with the information this tool is able to gather.  This amazing technology allows for tremendous insight into materials science.  In this field where there are countless different polymers, and crystals which are being grown and synthesized by scientists; having the ability to look this close at the structure of the material itself can lead to a much deeper understanding of how these materials actually form and function.

When I first heard that you could “grow” an LED or laser, I was shocked to say the least. I had never truly considered how solid state lasers were created until I got involved with research at the Center for Energy Efficient Materials (CEEM).  Once accepted to the program I found a lab to work in and was assigned a graduate student to mentor me.  The process has been very similar to an apprenticeship.  In a very short span of time I have learned how to use many different tools include a scanning electron microscope (SEM) and an atomic force microscope (AFM) and the crazy reactor they use to grow the devices with.

(XKCD)

I’ve been working with my mentor on making blue light emitting diodes (LEDs) and lasers now for a few months and it has been an amazing learning experience.  Blue is of particular importance because most white LEDs you see in flashlights or LED light bulbs in for use in homes are actually blue LEDs with a phosphor layer that makes them look white.  So in order to make good white lights, it is necessary to make good blue LEDs and lasers.

The process we use to grow these devices is called Metalorganic Chemical Vapor Deposition (MOCVD) which I know is a mouth full but typically is a machine that shoots various chemicals into a chamber for them to react and deposit material on top of a piece of sapphire.  Sapphire is nice because it has a similar structure to the material we want to grow on top, Gallium Nitride.

It’s an amazing feeling being on the inside of science helping with the progression of knowledge.  If you’re similar to me and like to read all about the latest scientific advances and all the amazing things scientists are creating then I’m sure you’ll find getting involved in research a very exciting and natural progression of this curiosity.