Every year, millions of tons of electronic gadgets are thrown into wastelands all over the world. This year alone, the United Nations' Solving the E-Waste Problem (STEP) estimates that gadget lovers will throw out a whopping 75 million tons of old laptops, smartphones, tablets and other devices in exchange for the latest ones released by their favorite manufacturers.
That is a huge amount of non-biodegradable waste, and it is a massive burden on the environment. This is why a group of researchers have decided to address the growing problem of e-waste by developing an environment-friendly solution to reduce the amount of toxic hazards we throw out into the environment by creating a semiconductor made out of wood.
Typically, wireless devices are powered by chips that use gallium arsenide, a compound known for superior high-frequency operation and power handling capabilities. But gallium arsenide is a hazardous material, particularly as seen in the context of the tremendous amounts of gadgets humans throw away every year. Wood, on the other hand, isn't dangerous to the environment. It is a renewable, biodegradable source that can be used to develop the support layer of a semiconductor.
"The majority of material in a chip is support. We only use less than a couple of micrometers for everything else," says Zhenqiang 'Jack' Ma, a professor of electrical and computer engineering at the University of Wisconsin-Madison who heads the research team. "Now the chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertilizer."
The researchers, working in collaboration with the Forest Products Laboratory of the Department of Agriculture, have developed a wooden semiconductor made from cellulose nanofibril (CNF) a flexible, biodegradable material made from wood. The result is an environment-friendly chip that the researchers say has "performance comparable to existing chips."
Two problems had to be contended with before the researchers reached this stage. First, wood is not as naturally smooth as other materials, and it can shrink or expand based on the temperature. To address these issues, the researchers applied a layer of epoxy coating on the CNS to smooth over its surface and close the moisture barrier.
Electronic manufacturers have no existing economic incentives to adopt wooden semiconductors, but researchers believe that companies will have to turn to environment-friendly means in order to sustain environment resources amidst a growing electronics industry.
"Mass-producing current semiconductor chips is so cheap, and it may take time for the industry to adapt to our design," says graduate student Yei Hwan Jung. "But flexible electronics are the future, and we think we're going to be well ahead of the curve."
The researchers have published their study in the Nature Communications journal.
