Light-emitting diodes with AlN polarization-induced buried tunnel junctions: A second look
Abstract
Interband Zener tunneling of electrons has been recently used in III-nitride semiconductor based light emitters to efficiently inject holes into p-cladding layers. Zener tunneling probabilities can be significantly enhanced if crystal symmetry-induced internal polarization fields assist the dopant-induced built-in electric fields of tunnel junctions because of the large reduction of the tunneling distance. In a metal-polar buried tunnel junction geometry, such electric field alignment needs an AlN interlayer at the tunnel junction. Because AlN is a larger bandgap semiconductor than GaN, it is not clear a priori if the net tunneling probability is reduced or enhanced compared to a homojunction. By combining theoretical modeling with experimental blue light emitting diodes, we find that the large tunneling enhancement due to the polarization field and band realignment overcome the reduction in tunneling due to the larger bandgap of AlN. Compared to a homojunction tunnel-junction, the inclusion of AlN in the tunnel junction is found to lower the turn-on and operating voltages and increase the wall-plug efficiency. This proves that polarization-induced AlN tunnel junctions are superior to homojunctions at low injection currents, resulting in higher optical emission intensity and superior uniformity.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 10, 2020
- Source ID
- 10.1063/5.0015097
Entities
People
- David A. Muller
- Debdeep Jena
- Huili Grace Xing
- Kevin Lee
- Len van Deurzen
- Shyam Bharadwaj
- Vladimir Protasenko
- Yu-tsun Shao
Organizations
- Air Force Office of Scientific Research
- Cornell University
- Division of Materials Research
- National Science Foundation