Money might not grow on trees, but soon electronic parts might. In a bid to try and make the production of electronic devices more sustainable and reduce waste, researchers have managed to develop a semiconductor chip made almost entirely out of wood. The paper is published in Nature Communications.
The scientists say that this demonstrates the ability to replace the support layer found in all computer chips with what they’re calling “cellulose nanofibril (CNF),” a biodegradable material made from trees. With consumer electronics typically made from oil-based plastics and other potentially toxic materials, the team hope that by moving to more sustainable materials that some of the problems of non-biodegradable waste might be alleviated.
“The majority of material in a chip is support,” says Zhenqiang Ma, one of the authors of the paper. This support makes up around 99% of the computer chip. “We only use less than a couple of micrometers for everything else. Now the chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertilizer,” Ma explained.
According to the researchers, over 426,000 cellphones were thrown in the trash every day in 2007 in the United States alone. With such rapid developments in tech, electronics are becoming increasingly disposable and with such massive consumption of non-biodegradable products, the environmental costs are continuing to mount. Add to this the frequent use of precious non-renewable natural resources and it’s not hard to see that such consumerism is not particularly sustainable.
Working from the University of Wisconsin-Madison, the team has been researching sustainable nanomaterial since 2009. By breaking wood down into even smaller units than the fibers typically used in paper production, they started looking at wood on the nano scale. From this, they were able to produce the very strong, flexible, transparent cellulose nanofibril paper. The problem with using wood in electronics, however, is getting the material smooth enough and stopping it from expanding.
“You don't want it to expand or shrink too much. Wood is a natural hydroscopic material and could attract moisture from the air and expand,” explains Zhiyong Cai, lead author. They were able to get around this by effectively covering the material in a thin layer of glue. “With an epoxy coating on the surface of the CNF, we solved both the surface smoothness and the moisture barrier.”
The researchers hope that the impressive flexibility of the material means it could be widely used in computer chips, and that the biodegradable properties of this new material will help make the electronics industry more sustainable and reduce reliance on the toxic material gallium arsenide currently used in many products.