Recombination in Polar InGaN/GaN LED Structures with Wide Quantum Wells

Abstract

The analysis of the photoluminescence of polar light emitting diode (LED) structures with a 25 nm In0.17Ga0.83N quantum well is reported. The observed emission most likely originates from a set of energetically close excited states (ES), while the ground state decays only extremely slowly on a μs‐to‐ms timescale, that is, long‐living charge accumulates there. However, this population can also be quantified spectroscopically by applying short reverse voltage pulses. The emission from ES is effective and nearly exponential with decay time constants of 1.5 and 8 ns at 6 and 300 K, respectively, and is likely dominated by radiative processes. These findings point to a possible route to improved polar device architectures.

Recombination kinetics in polar InGaN/GaN structures with wide quantum wells

“…1(b,c) are integrated spectrally, transients are obtained which show a clear single-exponential decay throughout the entire 5 to 300 K temperature range; see also our earlier results in Ref. 7 The time constant of the observed decay increases from 5 K to 300 K almost monotonically from 1...2 ns to about 7...9 ns, respectively. Such behavior is consistent with the assumption that this PL decay time is governed by radiative recombination.…”