Engineers map how heat kills efficiency in red LED materials
Researchers have identified exactly how temperature degrades the performance of InGaN quantum wells used in red LEDs and displays. The findings could guide manufacturers to design longer-lasting, more efficient light sources by engineering defect pathways that survive higher temperatures.
Originaltitel: Temperature-dependent carrier dynamics in red InGaN quantum wells revealed by cathodoluminescence
In this work, we investigate carrier recombination dynamics and defect-related emission behavior in high-indium content InGaN platelets containing a single quantum well (QW) and a transition layer (TL) using temperature-dependent monochromatic cathodoluminescence (CL) imaging and time-resolved CL (TRCL). At low temperature, monochromatic CL imaging reveals expanded apparent emitting area of both layers and reduced effective width of dark lines associated with stacking mismatch boundaries, indicating suppressed non-radiative recombination and enhanced alloy-induced carrier localization. The TRCL data reveal distinct temperature-dependent carrier recombination mechanisms governing both layers. At low temperature, carrier localization supports longer lifetimes (τ) in the QW of about 1.4 ns and the TL displays multiple recombination channels due to its structural complexity. At room temperature, thermal carrier diffusion enables efficient capture by defects, resulting in pronounced τ quenching to about 0.22 and 0.07 ns in the two layers, respectively.