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

Data are presented to quantify the effect of the conduction band energy barrier (ΔE_C,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 ΔE_C,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 ΔE_C,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 ΔE_C,B = 82 meV exhibits a longer recombination lifetime of 70 ps and a larger resonance peak of 4 dB.