Novel Design to Fabricate High Reflectivity GaN-Based Semiconductor/Air Distributed Bragg Reflector with the Tilt of Vertical Sidewall

High reflectivity can be reached with the proper design of a GaN-based semiconductor/air distributed Bragg reflector (DBR) structure even with a large vertical sidewall tilt. Finite-difference time-domain simulations show that vertical sidewall tilt is a crucial concern for obtaining a high-reflectivity DBR in a conventional design. A tilt of only 3 degrees reduces the reflectivity to approx 30%. Experimentally, it is difficult to etch vertical sidewalls of GaN-based materials. So, the novel design to obtain high reflectivity is important for the application of the GaN-based semiconductor/air DBR structure in waveguide lasers. 12 refs.