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 f(3 dB) of 4.3 GHz. The HBLET has a current gain, beta (=vertical bar Delta I(C)/Delta I(B)vertical bar) as high as 30, and can be operated as a three-port device to provide simultaneously an optical and electrical output with gain. The f(3 dB) 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.