Demonstration of an Integrated Multiquantum Well Heterojunction Bipolar Transistor with Gain for Efficient Low Power Optical Switching

An integrated low power optical device with cascadable properties is essential for general purpose optical processing systems. We propose and demonstrate such a device by placing an intrinsic GaAs/AlGaAs multiquantum well structure in the base collector region of an n- p-i-n heterojunction bipolar transistor. A gain of 50 is obtained by the MBE grown devices and efficient switching occurs due to the amplification of the negative resistance region of the exciton based photocurrent.