We create a reservoir of hole traps in a resonant tunneling light emitting diode by etching thep-type contact into an array of nanometer scale pillars. In the off state, the charge reservoir keeps the light output extremely low, even at relatively high currents. The device can be switched on to produce light by raising the electron emitter past a confined electron state allowing holes to escape from the nonradiative region. The resulting electro-optic switch has an on/off ratio of at least 1000:1, a large improvement over conventional resonant tunneling light emitting diodes. ©1997 American Institute of Physics.