BOFFINS HAVE COME UP WITH a better way of making light-sensitive semiconductors, which could lead to high-efficiency solar cells, better night-vision cameras and a host of other applications.

According to the popular science rag Nature, John Rogers from the University of Illinois has come up with a cost-effective technique to produce microchips made of the semiconductor gallium arsenide.

Gallium arsenide responds well to light and if swallowed will even send you to a white light at the end of a tunnel.

Rogers used a transfer-printing technique is used to peel and print thin layers of the semiconductor onto glass or plastic. This solved one of the problems of using GaAs in the semiconductor industry.

It means that this particular semiconductor can actually be used. It can theoretically convert about 40 per cent of incident solar radiation to electricity, making it twice as effective as silicon.

However the price of gallium arsenide is high because high-quality wafers of gallium arsenide must be grown in carefully controlled chambers. Much of the costly material is essentially wasted.

Rather than growing a single gallium arsenide layer, the team grew a 'pancake' of alternating layers of gallium arsenide and aluminium arsenide. Then, using a sequence of chemicals the team loosened the gallium arsenide layers and peeled them off with a silicon-based rubber stamp.

They stamped the wafers onto another surface, such as glass or plastic, and then etched the thin slices into circuits using more established techniques. µ