Electroluminescence observation of nanoscale phase separation in quaternary AlInGaN light-emitting diodes

摘要

Anomalous temperature-dependent electroluminescence u0001ELu0002 of Al0.06In0.02Ga0.92N/Al0.1Ga0.9Nnmultiple-quantum-well light-emitting diodes was investigated. At low temperatures and lowncurrents, the EL was dominated by narrow peaks arising from GaN band edge u00013.47 eVu0002 and AlGaNnlocalized state emission u00013.59 eVu0002. At 150 K, as thermalized carriers surmounted a static nanobarriernsurrounding In-rich nanoclusters, the EL shifted to low-energy emission at 3.39 eV. These ELnanomalies are evidence that, contradictory to theoretical predictions, there remains a strong effect ofncompositional fluctuation toward nanoscale phase separation in low In/Al AlInGaN alloys. Duringnthe interphase transfer at 150 K, the majority of excitons underwent nonradiative decay, leading tona sharp decrease in quantum efficiency by over one order of magnitude.