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Solar Cells Integrated In Microchips
cylonlover writes "In a new, more efficient approach to solar powered microelectronics, researchers have produced a microchip which directly integrates photovoltaic cells. While harnessing sunlight to power microelectronics isn't new, conventional set-ups use a separate solar cell and battery. What sets this device apart is that high-efficiency solar cells are placed straight onto the electronics, producing self-sufficient, low-power devices which are highly suitable for industrial serial production and can even operate indoors."
The same way EPROMs were: a standard opaque package with a quartz window.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Chip provides its own power
What one fool can do, another can. (Ancient Simian Proverb)
The exposure was my first thought as well, but from an electrical standpoint. A solar cell is just a diode with a large junction area, as I understand it, and most semiconductors are light-sensitive, so it didn't seem you'd want them exposed to intense light that causes currents to be generated throughout the circuit. But here they put the traditional circuitry on a layer below the solar cell. Still, as you note, the solar panel is so small that it generates very little power. If you increased its area, you'd increase the area of the underlying layer as well, which seems it'd increase its cost. Sure, it wouldn't have circuitry in the entire area, so the defect rate wouldn't scale as badly as it does for normal large chips, but it still seems it'd be cheaper to just use a separate solar panel of whatever size is needed. Maybe this would have a really specialized use.