Research in Biophotonics: Tools of the Trade

I love woodworking. Not saying that I’m great at it by any stretch, but I’ve found that in making cabinets, having the right tools makes all the difference in the world. It might be possible to find a table saw and router in the photonics center somewhere, but I haven’t seen any so far! More typically, high-level research calls for tools that are also highly technical, and which are based on science that’s not simple. To do their research, our group constructs microantennaes, like the ones shown in this image.

One thing that I found out is that the whole process involves a lot more chemistry than I would have thought. At every step, safety precautions are taken just like the ones we do at school, and more in a lot of cases. Here, they use organic solvents, and do everything under a fume hood, which is good because grad students care about their health too.

The first thing we did was to etch the pattern for our antennae using the electron beam machine. This was a lot like the process we used last year when we used photolithography to set up a design on a big silicon wafer. My friend John P. of Weymouth Physics fame did an awesome job explaining this process last year. And his blog is funny as all get out. Clean rooms will do that to people - it's gotta be the bunny suit.

After doing the first step with the e-beam machine, our chips had lots of tiny bowtie structures etched onto the surface of the wafer. The next step was to turn the outlines of bowties into things with holes in them, because the holes are key for getting light energy to go nuts in the structure.

The machine that does this is called the RIE, and it’s incredibly nasty – reactive ion etching would eat precise holes in your face if you climbed into the machine – wherever you didn’t have photoresistive material to protect you. Gas is introduced into the chamber, and it turned into a plasma by high-frequency radio waves. The plasma keeps eating silicon until you tell it to stop, so the timing of the operation is kind of a big deal.

After the RIE, we went to my favorite step – the one with the pellets of 99.999% pure gold as spray paint. Gold’s used a lot in nanotechnology for lots of reasons – it interacts really strongly with light and doesn’t react with anything in people to name two. We like it for the first reason, and to get this operation to work, we first mounted our chips upside down to the plate you can see in the picture.

Next, we put a pellet of our pretty pure gold int o a little crucible you see here. After closing down the hatch, the machine got to work creating a super-high vacuum. That took a while, but after that step, things heated up. A heating element (tungsten, I think) gradually raised the temperature to the point that the gold could vaporize.






Just like in the RIE machine, radio waves were used to excite the gold atoms, which helps them to vaporize into really tiny clusters.











At the end of the process, we had coated our bowties with gold, and they were ready for us to check out on the SEM.










In signing off for now, I would like to extend my heartfelt thanks to Serap, Ali and Prof. Altug. You were all so gracious in reaching out in the midst of your very busy schedules to teach, explain and sometimes, explain again. I know that I've gained so much understanding about what makes a research operation like this one tick - I'm sure my students and members of our school's sci-tech club will benefit. Thanks again for your support and commitment!

Research in Biophotonics: One bit at a time

When we left off, we were talking about the big picture in biophotonics, which has to do with getting the nitty-gritty information about what chemicals are doing what in disease processes. This is a tough trick because molecules are small, and because the ones we want to know about live inside of us, and not in test tubes. For the last reason particularly, Prof. Altug’s group has put a lot of effort into developing cheaper ways to build sensors that can be made cheaply, quickly and could be used not just in a lab, but also in actual living tissue.

I’ll explain a little bit about how Prof. Altug’s group is working to address these challenges, but I’d like to say two things. First, I would like to thank Serap Aksu, who always made herself available to lead the way and explain all of the many steps to the process we followed in making our sensors. Second, what I’m going to write about is research – some of this has already been published, but some if it hasn’t been yet, so I can explain in general what’s going on.

To begin with, here are a few pictures of the finished product. The bow-ties squeeze infra-red light energy into spaces that are much smaller than you could get normally. After doing some chemistry to the surface of the chip, antibodies that are designed to bond with a particular protein are added to it. Here, we’re looking at the antennae on the scanning electron microscope, which is an awesome tool by itself.

The SEM scans the surface of our finished product, gathering more scattered electrons from it when the SEM’s probe is closer to the work. In this way, the SEM can form images of very small items, and magnify things to an outrageous degree – like 500,000 X.

In the past few months, the group has created a couple of exciting developments – the first one is that they’ve perfected a system for making sensors more cheaply, and they’ve come up with ways to build sensors on soft materials, which is great, as it will enable sensors to be placed in a lot more places, like inside of us.

Next: Tools of the Trade

Research in Biophotonics: Big Picture

During the first several weeks of my RET program, I had the privilege of working on materials for the summer challenge program with our group’s research leader, Prof. Altug. This is always a great learning experience for me, and the chance to get to see her perception of developments within the field of photonics is invaluable – it’s really like being on safari with an expert guide. In the latter half of my time there, I got to be involved with the research end of the business, and was able to get to know a couple of graduate student members of her team as I participated in their research. Here, Alp checks out the result of some work he's done on his chips, while Serap waits to check on hers.

If you’ve followed the last entry about beating the diffraction problem, then you know that one of the keys to ultrasensitive detection of molecules is to focus light right where it needs to be. To do this, members of the Altug group, like Alp and Serap, have tried out many different designs for tiny antennae that can work this particular magic. Participating in this process was really educational on a couple of levels. Most importantly, everyone that I spent time with works incredibly hard at understanding each step of what they’re doing. Building and testing these tiny devices takes a few days at least, and everything is done along each step of the way to verify what’s been done. What I saw first-hand was a great example of how science really works - anyone who would ever doubt the honesty or ability of the people that I worked with just hasn’t seen these folks work up close.

So here’s the big picture: right now, screening for diseases like Alzheimer’s, Parkinson’s and many cancers is a hit and miss kind of deal. For example, breast cancer screens may miss what’s going on as much as 10% of the time. While there are some amazing new medicines out there right now that can work if the diseases are caught early, the tests that will tell you if you have the disease are still expensive and don’t work that well. The trick then, is to find which molecules will definitely mean that a particular disease is present or isn’t present.

Here’s a brand new one that seems to work: Alzheimer’s disease seems to be closely tied with a particular protein. In order to understand how the disease is working, what researchers would like to do would be to get sensing equipment actually inside of people who are developing the disease. That way, we’ll be able to really peel apart how the disease is operating, and know for certain if the biomarker is a clear indicator. And that’s another big aspect of Prof. Altug’s research – building better sensors so that researchers can speed up and improve their quest to exactly pinpoint the chemicals that are doing the dirty work in some of the nastiest diseases human beings can get.

Next: One little slice of the pie.

Summer Challenge!

Summer Challenge!

Providing clean water, ample food, high-quality medical care and education to people around the world are a few of the challenges facing the global community today. We know that when these things are in place, many other crucial social benefits like stable birthrates, can be achieved. Sustainability is at the heart of many of the grand engineering challenges, which I linked to in my first post this summer. One of the things that’s really significant to me about this list is that nanotechnology is going to play a significant role in achieving many of these goals. When biomedical testing can be made cheap enough that doctors can deliver the same high quality care in Boston as they can in Ghana, we will have really changed the world for the better.

Sharing this excitement was part of our challenge this summer as twenty high school students came to live at BU for two weeks, check out New England, and participate in a range of two-week mini classes. Toward the end of July, we met with our group of twenty students from San Francisco, China, Japan, New York, Texas, New Jersey, Virginia and Massachusetts to explore the basic science and new technology that is behind the developments at the Photonics Center. If you’ve followed some of my past blog posts, you have seen a lot of basic science – that light is made of small waves that bend around small things in a process called diffraction. This phenomenon is an example of super-important basic science. Here, Howard and Briana are talking through the math that explains that pattern of light on the white board, while Malika, our super undergrad engineering student looks on.

Why is it so important to understand how light and matter connect with each other? Because it’s the basis for an incredible array of new technologies – that’s why.

Take computers for an instance. As you may already know, one of the co-founders of Intel, Gordon Moore, published an observation in 1965 that became known as Moore’s Law. In that paper, Moore noticed that computer chips were becoming exponentially better, while at the same time becoming exponentially cheaper. It’s what’s behind every smart phone, every digital camera, and every other place chips find a hope, which is in almost everything we use today. However, as you might expect, there is a big problem with the idea of never-ending improvement. Today’s computer chips are smaller and faster than ever, but two things are happening.

1. is that they keep getting hotter. Like inside a nuclear reactor hot, or even hotter.
2. is that you can only make chips so small. Today’s transistors are around 25 nm. When designers get below 10 nm, Moore and others expect that electrons simply won’t behave themselves, and chips at that size will be useless.

Boom, done, end of high-tech industry as we know it.

This is where photonics comes in. What electronics was to the 1960’s, photonics is now: an evolving field that aims to do with light what Gordon Moore and others did with electrons back then. Right now, we use fiber optics to carry information around the world, but the insides of our computers are basically 1960’s type machines. Really tuned-up, but still things that run on electrons. Today, companies like Infinera and IBM, and research universities around the country are building the technology that will enable light to carry and process information through every part of the computer. This will create computers hundreds or thousands of times faster, while using much less energy than current ones do. The Infinera link takes you to a video that demonstrates a networking chip they’ve built. It’s not a whole computer yet, but it is a big improvement on that part of the system, and the technology is a step forward. This is part of what our students learned in summer challenge, and it’s a good backdrop for the research that I did on ultrasensitive biosensing. More on that soon!

Smart Lighting vs. Dumb Politics

[Warning: the following blog post contains opinions that may be objectionable to politically sensitive readers. Please, if you care for Bunnies at all, read on.]

The picture currently is that RPI and BU are leaders in a $20 Million dollar research effort designed to give U.S. companies a leg up in a field that will become known as Smart Lighting. The whole idea goes beyond saving energy, although that’s definitely part of it. As U.S. energy secretary put it recently, this type of energy savings is the “low hanging fruit” in building a sustainable energy economy - one that does not rely on burning vast amounts of imported oil. Here are the facts:

• 19% of electricity worldwide is used for lighting.
• There are over 30 billion light bulbs in use around the world, with most of them being traditional incandescent style.
• It’s estimated that all of these bulbs could be changed over by 2025, that the world would save 1 Billion Barrels of Oil each year – the equivalent of 250 nuclear power plants.Current lighting systems are beyond dumb – they’re just relics from a time when indoor lighting without having to burn kerosene or gas was a miracle of sorts by itself. What Smart Lighting entails is the use of LED lights (the type that are now used in that next fancy big-screen TV you want to get) to do several things:

• Save lots of money
• Last for a long, long time
• Provide light that is sensitive to the amount of natural lighting available, so that your home or office is never too bright or too dim for comfort
• Mimic the shifting color spectrum of light throughout the day, which works in support of our circadian rhythms. Yes, research says that current lighting in offices is not great for us, and that some folks react badly to it. This lighting will be natural.
• Provide the bandwidth needed to send GHz of data wirelessly, using pulsed visible light. This would be especially useful on airplanes and other places where heavy copper wire networks are bad for lots of reasons.
• And in a totally different setting, allow cars to communicate with each other and with traffic signals wirelessly, increasing safety

During George W. Bush’s presidency, members of both parties worked to develop legislation calling for higher standards for light bulbs. They ended up setting standards so that by 2012, light bulbs would have to be at least as efficient as the halogen bulbs you can buy today. Only the oldest style bulbs for sale today don’t make this standard, and they’re currently being re-worked by Phillips and other companies so that they’ll make it.

So who in the world would be against this kind of development? Well, Reps in Texas and South Carolina have written a law creating separate, worse standards for their states. The argument usually runs something like this:

“You can’t tell me what to do.”

I’ve gotta be honest – I cannot imagine a more backward-looking way to behave than this. With American kids fighting around the world in part to maintain our free access to oil, the people behind this kind of legislation aren’t just clinging onto the past – I really think they’re kicking away the future - in lives and money, while keeping us from moving in the direction of sustainability, which we simple must do.

The research money that our government is spending is designed to create a database of intelligence to help U.S. companies create a leadership position for our businesses in this area, which makes the sort of knee-jerk reaction to any type of standards just so frustrating to me. Being against U.S. energy independence is bad enough, but to be against the kinds of good quality jobs that are created by establishing U.S. leadership in an area is just not being a smart American. It's just an example of dumb politics.

Engineering the Future

Planning for this summer began a long time ago, back in August of last year. I felt very fortunate to have been able to be part of the goings on at the BU Photonics center in 2010, and spoke with Prof. Altug, my cooperating professor from BU about the possibility of coming back for a second visit. There were really two reasons for doing this – the first one was that we collaborated really well together and helped design some teaching materials that people seemed to like. The second was that seven weeks is waaayyyyy too short of a time to digest even a small percentage of what’s going on at a professional research facility, and I hoped to be able to learn more to bring back for my students. During the year, a few students at SJP and I

made some strides at helping bring more of an understanding of research science to the school, visited a couple of research sites and did some experimenting with lasers. Nanomaterials and Photonics are such hot topics in the world of research right now that both of the AAPT conferences I attended had it as their main topic, and I got to hear from many angles how the world of nano-research is shaping the future of engineering. Along the way in May, we heard back from NSF that our grant proposal for me to come back for another summer was approved – Psych!!

When June of this year rolled around, I got a surprise email from Prof. Altug asking me to go out to RPI for a conference. That turned out to be a fantastic experience – I love visiting schools to see what people do there, and I’d never been to RPI before. My awesome wife took a day off from work to come with me, and we made it into a road trip. What I saw was actually something like an audit – scientists and others from the National Science Foundation were conducting a public hearing of sorts where members of the RPI community described what they had been doing with the millions

in Federal grant money they’d gotten. I’m certainly no expert, but it seemed to me that NSF representatives asked a lot of tough questions, and challenged researchers not only to show progress, but also to prove that they were being responsible with their grant money. My little bit in the thing was to chat with people and explain to them what we had done during my summer RET experience, which turned out to be awesome.

I met with Prof. Ken Connor from RPI, and with professors from several other colleges in the research program, and we sat down together to share teaching strategies. Educational outreach is a huge part of work that professors do these days, and it’s a thread that will work its way through all of the blog posts that I do this summer. There has been a lot of talk centered on the need of U.S. schools to educate more engineers, and to educate citizens about what job opportunities exist in the future. In many ways, developing enough people with technical skills is a fundamental challenge that every society faces in the world today. The group’s work in Ghana centered around making

low-cost education in electrical engineering available through the mobile studio, a piece of hardware developed at RPI. The wealth of our countries is very different, but the challenge is the same – how to present students with a sense of the exciting challenges the future holds, while giving them the tools they need to tackle those challenges.

NanoBioTech@Brown

This weekend was a lot of fun! Twice a year, the local AAPT (American Association of Physics Teachers) group hosts a conference somewhere in the area. This year, it was at Brown University, and the topic was nanobiotechnology. That was awesome, because it was such a great fit with the research work that I was involved with this summer. The conference kicked off Friday afternoon, and went through Saturday afternoon, so there was a lot going on.

There were five or six talks where people presented their research, and it was pretty technical even though everyone tried to keep the math to a minimum. Consequently, I lived the weekend somewhere between "that's awesome!" and "uh-oh..what are they saying now?" The photo here is of Mark Reed from Yale University. Like a lot of research groups in nanophotonics, Mark's group is into a lot of different things all at the same time. Mainly, Mark spoke about his work with biosensors. He's doing his stuff in a different way from Hatice's research group, using computer chips to sense the presence of biological agents, but he's also gotten some really good results.

When researchers say that they can now sense 10^-15 moles of a

chemical, it kind of puts it into perspective when Mark compares that to putting a single grain of salt into an Olympic sized swimming pool! That really goes to a lot of the reasons why this new sensing technology is so cool. There are new meds for diseases like Alzheimer's and Parkinson's available, but they work the best when the disease is caught early. So for researchers like Hatice and Mark, the challenge is in trying to develop a practical way of sensing a small amount of a certain marker, like CA15.3, which is a marker molecule for breast cancer and many others. The way that his system works is that he builds nanowires from a single crystal of semiconductor. Then, they "functionalize" it by attaching a molecule that will bind with the disease molecule they're testing for. Because Mark's device is so sensitive to changes in the landscape around itself, they can tell very easily if they've got a hit in their blood sample or not. I talked with Mark after the conference, and his feeling was that human trials using his

type of technology are probably 1-2 years away, and that the plumbing of his device remains the big challenge.

That comment struck me, because I knew that our research group got itself on the cover of one of the big nanotech journals for coming up with one solution to that problem. I'll have to ask

Hatice or Ali next time I see them to see if their solution is one that he should be using or what the deal is there. One thing that I thought was funny was that he said "everyone always makes it sound so easy in their publications, but there's stuff they're leaving out!" That sounds like good old-fashioned gamesmanship to me!

There were a couple of other talks that were just awesome. I want to use them with my club's sci-tech club - totally inspiring and amazing! For a hint, google Naomi Halas and Peter Nordlander - they're a wife and husband team at Rice University, and had some really exciting stuff to share. More later!

Big Business, Little Bugs!

So this week took us WAYYYYYYYY further down the path of science fiction. I've been behind as a correspondent, so sorry for holding out on you.

We did a couple of really fantastic things this week, and also got some excellent swag courtesy of our excellent hosts at the BU Photonics center.

To begin with, we met with several folks from the BU business incubator, which sits on the 6th floor of the Photonics center. The notion, as we learned from David Bergstein of Zoiray Technologies is that small stuff if big business for a lot of reasons. David's company is small right now, and is in the process of trying to pull together venture capital to invest in their product. What was interesting to me was that their technology rests on the same footing as the group I've been working with. As a result, I understood what David was saying - it's all getting a response to very small amounts of certain kinds of chemicals. Those could be a protein if you're trying to detect Alzheimer's disease, or a reaction to an anti-virus if you're testing someone for Marburg. Ultimately, it's got to do with saving lives, and offering cutting edge medical testing to people without lots of money to pay for those tests.

We also heard from Tom Bifano, who is the director of the Photonics Center at BU. In addition to his work at BU, Tom gave us a look inside his own company, Boston Micromachines. Starting, as he said, with "a truly crappy product that really didn't work," Tom and his engineering staff have, several years later, developed an amazing device. The theory is simple: light gets distorted by all sorts of things around us - the atmosphere, water, and the goo in our eyes, to name a few. Where Tom's invention comes in is that it can sense incoming light, and warp the its mirrored surface to correct for these disturbances. The trick of this is that the mirror has thousands of bits that can be controlled by these tiny machines you see above, and that the mirror can change faster than the atmosphere or the goo in your eyes can mess things up.

All you have to do is to check out these two pictures to see why this is a big deal: On the top, we have a normal image of Jupiter taken from a good earth-based telescope. Below, you
see the image taken using Tom's company's adaptive optics. Pretty Amazing, huh?! Check out the link to Tom's company - what they are able to see while looking into your eyeball is pretty astounding!



OK, so back to the title of this week's blog, which said something to do with little bugs. This week, we also got to visit one of my favorite machines. It's such a favorite, that I am going to ask Dr. Hardiman & Dr. Shannon to get me one. I mean, us one - for the science department, of course!!

The SEM stands for scanning electron microscope, and it is quite an amazing machine. As you might have heard, light is a wave, and bends around stuff like all waves do. So, when you go to see really small things, you're in a lot of trouble, because light doesn't make clean shadows or outlines or anything really. Enter the electron: it can act like a wave of course, but when it does, its waves are very tiny, and it is great for seeing very small things.

So, we beat up a mosquito. It was dead long before we sprayed it with gold metal dust to make him show up more clearly on the SEM, so let me reassure you that no mosquitoes were harmed during this demonstration. As you can see, we zoomed down a long, long way.

I always thought those images of housefly eyes were pretty amazing - they still are, but the mosquito seems to have the same kind of
multiple eye-structure feature going on that the housefly does. At least that's what I think based on my limited bug knowledge. Better check with one of the bio people to be sure!

Like I said, I am no expert when it comes to bug parts, but this last image certainly looks like a bunch of cells to me. I have to check with somebody, because I'm really curious to know if we share some of our vision cells with the mosquito. Wikipedia says that the human cone cells can be around 500 nm - 4000 nm in size, so I'm still not sure exactly what I'm seeing here. In a human, the typical cell size is around
10 micro-meters, so maybe those big blueberry things are mosquito vision cells. Like I said, biology is a foreign country to me!

One final thought on that topic: at the end of the week, I again got to sit in on our research group's weekly meeting. Again, I was amazed to see John Connors from the BU Medical Campus explaining the important cell biology to the physics people in the group. That sort of give and take is so common around here - it's not the image of the lone scientist that gets played up in the media at all - it's much more of a team effort. Funnier too! John draws cartoons to show the physics people how a cell works, and the physics people explain to John just how they're going to attack resonances in the chemicals under study. It's pretty hilarious watching them go back and forth!

Rocking the Tiny World!

So today was nano-camp day!

Our intrepid group of four (me, Rick, Alex and Nick) have been working to lay the groundwork for this day for a couple of weeks. It was great to finally meet the brave students who had signed up to come to the Photonics center for the day to talk about the science of the very small. Our group of ten students were from all over the Boston area: Brighton, Chelsea, Brookline and Boston itself.
We met the students in the 7th floor chilling area and visited for a while. A number of the students, like Maganow and Yun said that they were considering doing engineering in college. A few said that they were undecided and looking at BU for college. A few were just hoping to do something fun for the day.

That part seemed to work out fine! Professor Altug is about as un-stuffy as you can get - she talked with the kids about what they'd been up to for the past few weeks before introducing them to nano-technology. She started with a version of the Powers of 10.
















If you've never played with the powers of 10 applet, you just have to!!! The universe is just an amazing place, and understanding the sizes of the places in it is the key to understanding a lot of other sorts of things. Prof. Altug rapidly took the kids from oak trees to dust mites to bacteria and other gross stuff. Looks nastier on the SEM!

After taking us through the basics of size, she took us through some other examples of nano-tech in modern life. There are more than I would ever have thought possible before starting this little research project. To begin with, quantum dot nano-particles of gold can be engineered so that they can target cancer cells. Because gold is great at turning certain frequencies of light into heat, it's possible to treat cancer using a laser that targets cancerous cells while leaving the healthy ones intact. Another great example from medicine is in the use of nano-particles in labelling cells of various kinds. With new drugs that can slow the spread of Alzheimer's disease, early detection of illnesses is more important than ever. Nanotech is making it possible for doctors to see diseases before they have a chance to get very far. As I've watched Alzheimer's progress in my own dad, I have seen first hand how great these new treatments are. There's still no cure, but this is a big stride forward. There are so many similar stories; different in their science, but the same in that scientists are unlocking the secrets of some of the world's worst killers, here and in the developing world. The hope of so many researchers is that nano-stuff can be made cheaply - cheap enough that doctors in rural Africa will be able to diagnose and treat as accurately as doctors in Danvers, MA.

So with visions of the micro-world burned into our frontal cortices, Nick, Alex and the others led the group up to our lab where we talked through a few important things, especially some pointers on laser safety. The point of our lab was to give students an idea how researchers use light to study the micro-world, and we started out studying some of our micro-samples under the stereo microscope.

At about 200X, you could see what the diffraction gratings were all about - that's actually connected with the real research that our group is doing. It's about a million times more complex, but the idea is the same, just that our group is working at the nano-scale.

After studying the gratings, the kids checked out what they did to light by focusing a green laser on a diffraction grating. Above, you can see Alex taking some readings on the laser beam spread after it's passed through the grating. Based on the wavelength of the light we used, the students were able to figure out the size of the features on the grating. On the left, Yun and Maganow are getting those numbers, while on the right, my partner Rick is helping out one of his students with the calculations.

After lunch, the students mixed up batches of PDMS gel, and coated their diffraction gratings. We put the samples in a vacuum chamber to get rid of the bubbles, which is important because it helps the goo get down into the tiny grooves in the sample. Then we went for a tour, checked out the clean room and some of the other labs around the building.

At the end of the day, the students pulled off their copies, and checked them out using lasers and microscopes. All I can say about this part is that some of them worked well!

The upward bound experience is a long one, and it's a pretty intense six weeks for the kids. They were great to work with though. Who knows if maybe some day they'll be back in that building helping to make some of the discoveries that'll shape their world.

Off to the Clean Room!

This week ended on a definite high note. After lots of not know where to go, and feeling like there was way too much to do, the week ended well. To begin with, our group pulled together some (I hope!) really good materials for NanoCamp. I've posted them over at my Physics 2H page at school, and I plan to use them this year - I think it'll be cool.

Second thing that went right was that we had a good week in the lab. Helen took us back up to the clean room where we got into the extra-clean bunny suits, just like before. She explained that we would be making a negative photoresist on silicon. For those of you who go to concerts and buy t-shirts, it's a lot like screen printing: (That's a link you should follow - it shows you how to screen print.)
Anyway, we did the nasty chemical process last week in making our photomask, and this week got down to business with putting copies of it onto silicon. Helen told us a story along the way that I thought was pretty amazing. Companies like Intel take their people who are the absolute best at spinning silicon disks and trust them with the huge wafers, like that guy is holding up top. She said that if one of those gets dropped, it's thousands of dollars down the drain, and one person banished back to the ordinary clean room. Sad!

We weren't working with any super-expensive units this day, but we did have to be careful. We were spinning 4" silicon disks on the disk spinner (it has a real name but I forgot it.) BTW, you can see how shiny the Silicon discs are - that's John's smiling face reflecting in the wafer that Helen is holding.

Anyway, this part is kind of an art, and it's also a lot different from t-shirt silk screening, too. In putting tiny patterns onto these chips, you can control some of the size of the patterns by controlling the thickness of the photoresist you put on the wafer. And so we have the wafer spinner - works like a carnival spin art machine, except is puts down something like 50-200 micrometers of goo depending on the goo and how you spin it.

After spinning on the photoresist, we baked our wafers in a couple of stages, and then took them to be "screen printed." In reality, we went back to the Suss machine and used our mask to expose our wafers to UV light. Again, wherever we didn't have mask, the photoresisting material gets exposed, cross-links and becomes permanent. Once we wash off the remaining unexposed goo with acetone, we're left with a slick, shiny wafer that has micro-structures cut into it. We looked at our pattern under the microscope, and it looked kind of like this image on the left. This part's beginning to make sense!

Also, what makes me happier is that I can see how what we're doing in the lab fits with what my research group is doing. More on that in the next post, I think!

Reflections for Week Two

Two weeks gone by, and it looks like we're starting to move forward. Here are my responses to the questions we've been given for reflection. Bear in mind that our group is working differently than some others.

What is the hypothesis you are testing?
We aren't testing any hypothesis, unless it was that four unrelated people from very different backgrounds can form a group and crank out good work! Our group is not even doing any research. We are building a product (a series of labs) that will have a definite outcome, so what we're doing is more engineering than science. Good stuff though, but not anything like textbook science.

What kinds of controls does the experiment have?
Hmmmm.... don't know how to answer that at all.

How will you measure your results?
This we can do - we get to run one lab with the high school kids before we use it on the college kids. That's the only measuring we can really do though.


How will the reliability of your data be ensured?
Now this question I like: I think that one thing that has really changed my teaching career has been microsoft word. For me, every thing I try - every test, quiz or homework is a question that I ask the guys in my classes. The key to making things better for the kids isn't to be perfect, it's just to keep on improving, and to use the results you get to see how get there. So the answer to the question is that we record everything. If the folks who come after us want to improve, they can look at our notes and see what we were thinking of. Student tests can be data just as much as lab data can be data. All just facts you're gotta keep track of.

How will inquiry fit into your lesson plan?
This is interesting - we're creating some actual labs, so we might have room to frame the labs to include some inquiry. Definitely, we're putting some puzzles into the program for students to work on, but we're building a product for our professor, who gets to decide just how much inquiry based stuff there will be in there. We'll see!