Processors do grow on trees: your next phone could be made of wood

Engineers hunting for a way to make electronics more sustainable have hit on a novel invention - a semiconductor chip made almost entirely out of wood.

The idea is that instead of making chips from petroleum-based plastic, we'd be able to use cellulose nanofibril - a flexible, biodegradable material that's made from plants. "The majority of material in a chip is support. We only use less than a couple of micrometers for everything else," said Zhenquang Ma, who lead the team.

The researchers have been studying bio-based polymers for more than a decade. While they showed some promise, there were a couple of key problems - wood's rough surface, and how it responds to moisture and 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 Zhiyong Cai, who also contributed to the discovery. "With an epoxy coating on the surface of the [material], we solved both the surface smoothness and the moisture barrier."

The result is a bio-based chip, which is not only flexible enough to use in consumer electronics but an order of magnitude more environmentally-friendly. "The chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertilizer," said Ma.

He added: "Mass-producing current semiconductor chips is so cheap, and it may take time for the industry to adapt to our design. But flexible electronics are the future, and we think we're going to be well ahead of the curve."

The research was published in Nature Communications.