A quantum interference transistor comprising an source region for emitting electron waves into a vacuum, a drain region for collecting the electron waves, a repeating nanostructure in a region between the source and drain regions for introducing a constant phase shift between a plurality of electron waves, and a gate for controlling the phase shift introduced by the nanostructure; wherein the repeating nanostructure is characterized by having sharply defined geometric patterns or indents of a dimension that creates de Broglie wave interference.