Tamm plasmons in metal/nanoporous GaN distributed Bragg reflector cavities for active and passive optoelectronics
Abstract
We theoretically and experimentally investigate Tamm plasmon (TP) modes in a metal/semiconductor distributed Bragg reflector (DBR) interface. A thin Ag (silver) layer with a thickness (55 nm from simulation) that is optimized to guarantee a low reflectivity at the resonance was deposited on nanoporous GaN DBRs fabricated using electrochemical (EC) etching on freestanding semipolar (20 21 ¯ ) GaN substrates. The reflectivity spectra of the DBRs are compared before and after the Ag deposition and with that of a blanket Ag layer deposited on GaN. The experimental results indicate the presence of a TP mode at ∼ 454 nm on the structure after the Ag deposition, which is also supported by theoretical calculations using a transfer-matrix algorithm. The results from mode dispersion with energy-momentum reflectance spectroscopy measurements also support the presence of a TP mode at the metal-nanoporous GaN DBR interface. An active medium can also be accommodated within the mode for optoelectronics and photonics. Moreover, the simulation results predict a sensitivity of the TP mode wavelength to the ambient (∼ 4-7 nm shift when changing the ambient within the pores from air with n = 1 to isopropanol n = 1.3), suggesting an application of the nanoporous GaN-based TP structure for optical sensing.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 01, 2020
- Source ID
- 10.1364/oe.392546
Entities
People
- C. Symonds
- Guillaume Lheureux
- J. A. Schuller
- J. Bellessa
- James S. Speck
- Morteza Monavarian
- R. A. Decrescent
- Richard H. Anderson
- Shuji Nakamura
- Steven P. DenBaars
Organizations
- National Science Foundation
- Office of Naval Research
- Simons Foundation
- Solid State Lighting and Energy Electronics Center, University of California Santa Barbara