Ultra-Short Lifetime of Intersubband Electrons in Resonance to GaN-Based LO-Phonons at 92 meV

Abstract

In this study, we report on the ultra-short lifetime of excited intersubband electrons in a 38 Å wide AlGaN/GaN-based quantum well. The rapid decay of these charge carriers occurs due to a resonance between the relevant intersubband transition energy and the size of the GaN-based LO-phonon at 92 meV. Based on the experimentally observed Lorentz-shaped intersubband emission peak with a spectral width of roughly 6 meV (48 cm−1) respecting the Fourier transform limit, a very short lifetime, namely 111 fs, could be calculated. By comparing this lifetime to the existing literature data, our value confirms the potential high-speed capability of III-nitride-based optoelectronics.