It was sometime in August, 2006. I had just received a package that I had been waiting weeks for: the brand new MacBook , fresh from a factory in China. I set it on my kitchen table, plugged it in, and turned it on. After a few minutes of playing with my new toy, my friends shouted at me to bring it over to the living room. I unplugged the machine, walked over to them, and sat down.
Remember now, a minor but important detail of this story is that it was August. That means it was hot. That means I was wearing shorts. For those of you who remember the first set of MacBooks, this is a big hint on how this story ends.
As I sat down, the plastic underbelly of the case touched my legs and I about threw the machine across the room. The MacBook was approximately 15,000 degrees. I looked down and saw my upper leg hairs were sizzling. It looked like a snowy version of the burned rain-forest in Fern Gully (I have pale, hairy thighs. You're welcome for that visual).
OK. So maybe it wasn't that bad, but the machine definitely ran hot. Why? Because the silicon used in the chips for the computer and the lithium ion couldn't handle the electricity and the power that couldn't be used was put off as heat.
You may notice this phenomenon in other products like phones, video game consoles, cameras, and light bulbs. When you use them, they get hot. Light bulbs for example only use 5% of the energy they receive for making light. The other 95% of the energy is converted into heat. In other words, if you are paying $10 to use a light bulb for a month, only $0.50 is being used for light and the other $9.50 is being wasted as useless heat (unless you are using a ton of light bulbs to try to heat your house). In the same way, when you pay to charge your phone, turn on your TV, or use your laptop, you are paying for a lot of wasted energy.
Or at least that's the way things used to be.
Current Energy Waste
Wide bandgap semiconductors are power cells that are being used to reduce the waste that occurs when you use an electronic device. The claim is that wide bandgap semiconductors will be able to reduce wasted energy by 90%. That means that now 85% of the energy you use for a light bulb will actually go towards creating light rather than 5%.
But, if you're anything like me, you're thinking, "Huzzah! But, uh, what the heck is a wide bandgap semiconductor?"
What Is a Semiconductor
Well, let's break it down. A semiconductor is in the middle ground between a conductor, something that electricity can easily move through, and an insulator, something that electricity cannot move through. Suffice to say, a semiconductor allows electricity to move through it in a controlled manner.
What does it mean when a semiconductor has a wide band gap? Well a band gap is the amount of energy it takes to move electricity across the material. The higher the bandgap, the more energy it takes. That leaves us with a question then: if wide bandgaps take more energy to get energy across them, then why would we want to use something like that to lower energy costs? Great question.
Wider Is Not Necessarily Better
First off, "wide" does not equal "better." For example, a diamond has a wide band gap but it cannot conduct electricity. What researchers are looking for is a material that has a bandgap that matches the incoming power source. Here is an analogy: think of a river dam where the water is the energy and the dam is the bandgap. If the river is 20 feet wide and has a 5 foot space to go into, the water that does not go into that five foot space will hit the wall and bounce back and the energy of the moving water will be lost. If the river is 5 feet wide and has a 20 foot space to go into, it will flow through the gap with no speed and no energy. But, if the river is 10 feet wide and the gap for the river to go through is 10 feet wide, then all of the energy the river is carrying will go through the gap.
The "wide bandgap" is not trying to be wider for wider's sake, but is trying to match the incoming energy source. Silicon is like having a 5 foot wide gap and a 100 foot wide river. A lot of energy is wasted when the rushing river hits the gap. But wider band gaps allow for the energy of the rushing river to pass through efficiently.
More Efficient...and Smaller!
Not only does using materials with wider bandgaps make the energy use more efficient, but it means you can make the items smaller. Think about it. If you have to have the 100 foot wide river of power to run your device and all that power has to go through a silicon chip that is only 5 foot wide, you'd have to have twenty silicon chips to conduct all the power. But if you have a silicon carbide chip that has three times the bandgap of silicon, then you'd only need 6.67 silicon chips. The silicon chips are more efficient and you need less of them. Now we are working with smaller, faster semiconductors.
Knowing this, it starts to make sense why President Obama would want to create a hub that brings together manufacturers and engineering universities in Raleigh, NC to work on developing these new semiconductors. These things could change the way our world works. Faster computer processors. Longer lasting phone batteries. Electric cars that you could actually road trip in. Refrigerators with coils that don't double as griddles. The possibilities are astounding!
But honestly I'd just be happy if I could put my laptop on my lap without fearing for future generations.