A team of scientists have recently invented the world’s first biodegradable wood-made semiconductor chip.
As electronics have gained ground in our contemporary societies, so has e-waste. As a matter of fact, when we dispose of used electronics, they do not get biodegraded; they thus constitute a waste of space, as well as pollutants in the form of the toxic chemicals they contain. Consequently, we now have a total of 41.8 million tonnes of e-waste dumped all across the globe. To counter this growing problem, scientists from the US have invented a biodegradable high-performance semiconductor chip made of wood. The research is described in a paper published in the journal Nature Communications.
“The majority of material in a chip is support. We only use less than a couple of micrometers for everything else,” one of the team members, engineer Zhenqiang Ma from the University of Wisconsin-Madison, said in a statement.”Now the chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertiliser.”
The usual support layer of the ‘green’ chip is substituted with a flexible and biodegradable layer of cellulose nanofibril (CNF). CNF, derived from wood broken down to its nanoscale fibers, is strong and transparent. CNF was found to be the ideal material to use as support later for the chip: it is smooth, and has the capacity to expand with heat.
“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,” said Shaoqin Gong, one of the researchers. “With an epoxy coating on the surface of the CNF, we solved both the surface smoothness and the moisture barrier.”
Another author, Yei Hwan Jung, commented on their work as follows:-
“I’ve made 1,500 gallium arsenide transistors in a 5-by-6 millimetre chip. Typically for a microwave chip that size, there are only eight to 40 transistors. The rest of the area is just wasted. We take our design and put it on CNF using ‘deterministic assembly technique’, then we can put it wherever we want and make a completely functional circuit with performance comparable to existing chips.”
The scientists hope that their invention will be used by electronics companies in the future.
“Mass-producing current semiconductor chips is so cheap, and it may take time for the industry to adapt to our design,” said Ma. “But flexible electronics are the future, and we think we’re going to be well ahead of the curve.”