Near-UV Electroluminescence in Unipolar-Doped, Bipolar-Tunneling GaN/AlN Heterostructures
Journal Article - Open Access
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
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Cross-gap light emission is reported in n-type unipolar GaNAlN double-barrier heterostructure diodes at room temperature. Three different designs were grown on semi-insulating bulk GaN substrates using molecular beam epitaxy MBE. All samples displayed a single electroluminescent spectral peak at 360 nm with full-width at half-maximum FWHM values no greater than 16 nm and an external quantum efficiency EQE of approximate to 0.0074 at 18.8 mA. In contrast to traditional GaN light emitters, p-type doping and p-contacts are completely avoided, and instead, holes are created in the GaN on the emitter side of the tunneling structure by direct interband that is, Zener tunneling from the valence band to the conduction band on the collector side. The Zener tunneling is enhanced by the high electric fields similar to 5 x 1,000,000 V cm-1 created by the notably large polarization-induced sheet charge at the interfaces between the AlN and GaN.
- Electricity and Magnetism