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Nanowire Silicon Solar Cell for Powering Small Circuits

Harvard group builds working photovoltaic cell just 300 nanometers across

3 min read

18 October 2007--A new type of solar cell made from a nanometer-scale wire might one day provide an on-chip power source for nanoelectronic devices or run microscopic robots, say scientists at Harvard University.

The solar cell is a coaxial silicon nanowire, approximately 300 nanometers thick. In experiments, it produced 200 picowatts of electricity, a tiny amount to be sure, but enough that it was used to operate a nanowire-based pH sensor. Chemistry professor Charles Lieber and members of his research group at Harvard described the device in the 18 October issue of the journal Nature .

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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