Electroluminescence in n-type GaAs unipolar nanoLEDs

In this Letter, we report the observation of electroluminescence (EL) at ~866 nm from 𝑛-𝑖-𝑛 unipolar (electron-transporting) III-V GaAs nanoLEDs. The devices consist of nanopillars with top diameter of 166 nm, arranged in a 10×10 pillar array. Hole generation through impact ionization and Zener tunnelling is achieved by incorporating an AlAs/GaAs/AlAs double-barrier quantum well within the epilayer structure of the 𝑛-𝑖-𝑛 diode. Time-resolved EL measurements reveal decay lifetimes >300 ps, allowing us to estimate an internal quantum efficiency (IQE) higher than 2% at sub-mA current injection. These results demonstrate the potential for a new class of 𝑛-type nanoscale light-emitting devices.