Nuclear-powered pocket gadgets may be possible, according to a University of New Mexico patent application (US 2004/0154656). When beta radiation from titanium tritide, a compound of radioactive tritium, hits a junction between p-type and n-type semiconductors, a current flows across the junction. But until now the amount of radiation needed to do this has been too high for safe personal use.
UNM’s idea is to etch hundreds of deep holes in a wafer of n-type gallium phosphide, and coat the shaft walls with p-type impurities to create the junctions. Etching shafts with a 100:1 depth to width ratio improves power generation 400 times, says UNM.…
