The Green’s Function Description of Emission Enhancement in Grated LED Structures

Using scattering to improve light extraction from semiconductors is a widely adopted method to increase the efficiency of modern light-emitting devices. Recently, there has also been much interest in the potential emission enhancement provided by the strong coupling between surface plasmons and semiconductor emitters. In this study, we develop a Green´s function-based model to describe the emission enhancement and modification in optical properties obtained as a result of scattering and plasmon engineering. The Green´s function method is used to answer fundamental questions regarding luminescence enhancement in periodically grated GaN light-emitting structures. The Green´s function approach is a very attractive analytical method to studying the emission properties of grated multilayer structures, providing insight beyond numerical solutions. Modeling results from reflectometry measurements of silver-grated GaN structures allows to explain experimentally observed interference features. A discussion regarding the role of periodic grating in enhancing emission from the structures is included.