Chip-Scale Droop-Free Fin Light-Emitting Diodes Using Facet-Selective Contacts
Robin P Hansen1, Yuqin Zong1, Amit Agrawal1,2
1National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
ACS Applied Materials & Interfaces
|September 8, 2021
Summary
Researchers developed droop-free fin light-emitting diodes (LEDs) that achieve microwatt output powers. This scalable method enables high-brightness ultraviolet light sources for demanding applications.
Area of Science:
- Optoelectronics
- Semiconductor devices
- Nanotechnology
Background:
- Sub-micron light sources suffer from low power (nanowatts) due to current density and temperature droop.
- Previous work introduced droop-free fin LED pixels achieving microwatt output powers at high current densities.
Purpose of the Study:
- To demonstrate a scalable method for electrical injection into sub-200 nm wide n-ZnO fins on p-GaN.
- To fabricate and characterize electrically addressable fin LEDs for high-brightness applications.
Main Methods:
- Selective metallization of fin nonpolar side facets.
- Fabrication of linear arrays of fin LEDs using 2 μm photolithography.
- Electroluminescence analysis at high current densities (100-2000 kA/cm²) and temperatures (200-340 °C).
Main Results:
- Achieved electrical injection into sub-200 nm ZnO fins with 0.8 μm² active area.
- Fin LEDs emit narrow-band UV light (≈368-390 nm).
- Emission intensity increased with current density without droop, even at high temperatures.
Conclusions:
- The fin geometry effectively suppresses nonradiative recombination pathways like Auger recombination.
- This approach enables high-brightness, sub-micron light sources operable at high temperatures and current densities.
- The technology is suitable for advanced optoelectronic applications requiring compact, powerful light emitters.
