Getting the Heat Right for CNT Fabrication
If you’re growing carbon nanotubes, you know the struggle. You need an incredible amount of heat, and it has to hit the wafer surface exactly right. If that energy leaks out into the chamber walls, you’re basically throwing money and time away. That’s why we use gold-coated reflectors. It sounds fancy, but the goal is simple: make sure every single watt of power actually hits the substrate.
Why gold?
Most people start with aluminum reflectors. They’re common, sure. But here’s the problem—aluminum just absorbs and scatters too much energy when you’re dealing with short-wave infrared. It’s leaky. Gold is different. It’s a beast when it comes to reflecting infrared radiation. By lining the chamber with gold-plated optics, we’re essentially bouncing the heat back toward the wafer. It creates this tight, focused zone of energy. You get to your fabrication temperatures way faster, and the heat stays where it belongs.
It’s about density, not just raw power
When you’re cranking up the wattage, you aren’t just looking for “hot.” You’re looking for energy density. With gold reflectors, we can concentrate that flux. This is a huge win because you can hit the activation energy needed for those CNTs to grow without pushing your lamps so hard that they burn out early. But there’s a catch. Because the heat is so concentrated, you have to be obsessive about your setup. If your wafer is off by just a few millimeters, you’ll get uneven growth across the surface. Your mounting hardware has to be spot on.
The trade-off
Now, gold isn’t perfect. It’s soft. If you go in there with abrasive cleaners or start scrubbing the surfaces, you’re going to ruin them. One deep scratch and you’ve just created a “cold spot” in your radiation field, which throws everything off. We tell everyone to stick to a strict non-contact cleaning routine. Keep the gold pristine, use the right optics, and you’ll get way more out of every kilowatt you pump into the system.