The information age has produced astonishing improvements in compute power, but the current highly successful CMOS technology is running into power limitations. Computing takes up of order 5% of the US electricity production, power is now the primary limiting factor on clock speed, and power limits practical development of exascale computing facilities. CMOS power depends on voltage which is now limited by fundamental physics and cannot be further lowered by an engineering fix. A fundamentally new device concept is needed in order to take computing into a new lower power regime. © 2013 IEEE.