Motivated by the emergence of materials with mean free paths on the order of
microns, we propose a novel class of solid state radiation sources based on
reimplementing classical vacuum tube designs in semiconductors. Using materials
with small effective masses, these devices should be able to access the
terahertz range. We analyze the DC and AC operation of the simplest such
device, the cylindrical diode magnetron, using effective quantum models. By
treating the magnetron as an open quantum system, we show that it continues to
operate as a radiation source even if its diameter is only a few tens of
magnetic lengths.Comment: 11 pages, 7 figures; submitted to Physical Review Applie