http://www.nature.com/nature/journal/v526/n7571/full/nature15387.html (http://www.nature.com/nature/journal/v526/n7571/full/nature15387.html)
Here we demonstrate band-to-band tunnel field-effect transistors (tunnel-FETs), based on a two-dimensional semiconductor, that exhibit steep turn-on; subthreshold swing is a minimum of 3.9 millivolts per decade and an average of 31.1 millivolts per decade for four decades of drain current at room temperature. By using highly doped germanium as the source and atomically thin molybdenum disulfide as the channel, a vertical heterostructure is built with excellent electrostatics, a strain-free heterointerface, a low tunnelling barrier, and a large tunnelling area. Our atomically thin and layered semiconducting-channel tunnel-FET (ATLAS-TFET) is the only planar architecture tunnel-FET to achieve subthermionic subthreshold swing over four decades of drain current, as recommended in ref. 17 (http://www.nature.com/nature/journal/v526/n7571/full/nature15387.html#ref17), and is also the only tunnel-FET (in any architecture) to achieve this at a low power-supply voltage of 0.1 volts.
Fine but what is needed is a power-FET able to switch at nanoseconds at 400VDC with breakdown voltage around 1kV, switching in pulse thousands of amperes. Ideally driven from a 3.3V source with driver with fast gate charge filling and fast turnoff.