Fast non-equilibrium carrier dynamics in polar InGaN/GaN structures with wide quantum wells

Abstract

We analyze the time-resolved photoluminescence (PL) from the bulklike continuum of excited states of 450 nm emitting InGaN/GaN device structures that are based on wide quantum wells with 25 nm thickness. In its spectrally integrated form, the PL behaves as if it were dominated by radiative recombination, including an almost exponential decay reflecting the radiative lifetime. If the PL is resolved spectrally, a very broad spectrum of time constants is found, from ps to ns. At low temperatures, we detected PL decay as fast as (16 ± 2) ps. This PL is assigned to hot carrier PL within the bulklike quasi-continuum of states of these promising structures. Theoretical modeling supports this interpretation of our experimental results.