Scientists at the University of Wisconsin-Madison have published a paper demonstrating a semiconductor made almost entirely of wood, dubbed a cellulose nanofibril (CNF) chip.
Designed during research into reducing the environmental impact of today's high-tech industry, the researchers at Wisconsin-Madison teamed up with members of the US Department of Agriculture's Forest Products Laboratory under the leadership of Zenqiang 'Jack' Ma to investigate the feasibility of replacing the substrate layer of a working semiconductor with cellulose nanofibril, an environmentally-friendly material made from wood.
'The majority of material in a [semiconductor] chip is support. We only use less than a couple of micrometers for everything else,
' Ma explained of his team's research. 'Now the chips are so safe you can put them in the forest and fungus will degrade it. They become as safe as fertilizer.
Zhiyon Cai, who has been working on sustainable nanomaterials since 2009 as project leader for an engineering composite science research group at the Forest Products Laboratory, explains the process: 'If you take a big tree and cut it down to the individual fibre, the most common product is paper. The dimension of the fibre is in the micron stage. But what if we could break it down further to the nano scale? At that scale you can make this material, very strong and transparent CNF paper.
This CNF 'paper' is then treated using techniques developed by Shaoqin 'Sarah' Gong and her team at Wisconsin-Madison, which uses a thin coating of epoxy to smooth the surface, control thermal expansion, and prevent the wood-based material from absorbing moisture from the surrounding air.
The research team claims that CNF-based chips could prove a direct replacement for gallium-arsenide chips with similar performance at a far lower environmental cost. The team's research has been published this week in the journal Nature
, but thus far no timescale has been given for the technology's commercial exploitation.