Study On The Local Luminescence Enhancement Effect Of Surface Plasmons

Surface plasmons(SPs)is a kind of electromagnetic wave localized on metal Surface,which has the local electric field enhancement effect and high density of states.It has great application value to understand the effect of SPs local characteristics on spontaneous emission and internal quantum efficiency(IQE)of the semiconductor light emitting structure.From the perspective of energy conservation,this paper theoretically analyzes the three energy transfer modes and processes when semiconductor luminescence structure is coupled with SPs.The density of photon state,the density of electron state,spontaneous radiation rate and other microscopic quantum mechanical parameters involved in the luminescence process are analyzed in detail.According to Fermi golden rule,the effect of electron-hole pairs on spontaneous emission rate under the SPs is studied,in which the distance between dipole matrix element and metal plays an important role.Through detailed analysis of the coupled luminescence process of metal SPs and semiconductor,some ideas are provided for the research of the SPs coupled optoelectronic devices.In this paper,finite element method(FEM)and finite difference time domain method(FDTD)are used to study the coupling between Si-based indirect band-gap semiconductor light emitting structures and SPs.The effect of the size and period of the typical metal nanoparticles on the resonance peak of Si-based structure is analyzed.In addition,due to the low luminescence efficiency of Si-based semiconductor structures,the tip effect is introduced to enhance the optical power of Si-based structures.The results obtained by the FEM show that the coupling of SPs and indirect bandgap luminescent materials can improve the light emitting efficiency.In this paper,the Purcell effect of GaN light-emitting structure was also studied by using FEM and FDTD.Through the relationship between Purcell factor and the peak of surface plasmon resonance,the effect of material,diameter,spacing of metal spherical nanoparticles and the position of electron-hole pairs on spontaneous emission rate of GaN-based structure was studied.At the same time,the multi-quantum-well(MQW)GaN light-emitting structure model was designed to obtain the average Purcell factor,and the lifetime decay curve of the experimental sample was analyzed by photon lifetime test to verify the relationship between Purcell factor and photon lifetime.The average relative error between the experimental lifetime values and the theoretical values are all less than 0.07.