4.3 GHz optical bandwidth light emitting transistor

We demonstrate a quantum-well base heterojunction bipolar light emitting transistor (HBLET) operating in the common collector configuration with a 3 dB optical response bandwidth $f3dB$ of 4.3 GHz. The HBLET has a current gain, $β$ $(=|ΔIC/ΔIB|)$ as high as 30, and can be operated as a three-port device to provide simultaneously an optical and electrical output with gain. The $f3dB$ of 4.3 GHz corresponds to an effective carrier recombination lifetime of 37 ps, and shows that “fast” spontaneous recombination can be harnessed for high-speed modulation.