Ultrafast Radiative Recombination Engineering in InGaN/GaN Quantum Wells through Temperature, Alloy Fraction and Layer's Width Tuning for Photonics

Abstract

Radiative lifetime (RT) on the picosecond to femtosecond scale plays a key role in enabling ultrafast optoelectronic technologies. This study investigates the RT in InGaN/GaN quantum wells (QWs), focusing on the effects of well thickness, temperature, and indium (In) composition using the finite element method. The results show a significant dependence of RT on these parameters for both subband (ISB) and band-to-band (BTB) recombination. Specifically, radiative lifetime for ISB transitions extend to nanosecond timescales, with values reaching up to 6 ns, reflecting reduced wave function overlap and lower recombination probabilities at higher temperatures. In contrast, BTB recombination exhibits much faster dynamics in the fs range, with lifetimes as short as 10 fs, which is critical for high-speed applications. This research highlights the importance of precisely controlling QWs parameters, as well as internal and external factors, to optimize device performance in emerging InGaN-based ultrafast technologies.