  We present results on electrically driven nanobeam photonic crystal cavities
formed out of a lateral p-i-n junction in gallium arsenide. Despite their small
conducting dimensions, nanobeams have robust electrical properties with high
current densities possible at low drive powers. Much like their two-dimensional
counterparts, the nanobeam cavities exhibit bright electroluminescence at room
temperature from embedded 1,250 nm InAs quantum dots. A small room temperature
differential gain is observed in the cavities with minor beam self-heating
suggesting that lasing is possible. These results open the door for efficient
electrical control of active nanobeam cavities for diverse nanophotonic
applications.
