Effect of the energy barrier in the base of the transistor laser on the recombination lifetime

Abstract

Data are presented to quantify the effect of the conduction band energy barrier (ΔEC,B) in the base region of the transistor laser on the minority carrier transport dynamics, recombination lifetime in the base region, and frequency response of the device. A greater ΔEC,B results in lower transistor current gain (β) and higher optical output power, indicating increased carrier confinement and recombination in the base. For a device with ΔEC,B = 41 meV, the measured bias-dependent optical frequency response and subsequent data fitting yield a short recombination lifetime of 30 ps in the base and a small resonance peak of 1.5 dB. A device with ΔEC,B = 82 meV exhibits a longer recombination lifetime of 70 ps and a larger resonance peak of 4 dB.