Investigation of plasmon-induced extraction efficiency enhancement in a CdTe-based LED using FDTD simulation

Light-emitting diodes (LED) based on silicon platforms and CdTe quantum dots (QDs) are an important area of research. Due to poor charge balance in QD layers, reduced graphene oxide (RGO) was introduced between the P-Si substrate and CdTe QDs. To further improve the performance of the QDs-LED, Au nanorods (NRs) were incorporated into the hole transport layer. A finite-difference time-domain simulation was used to discuss theoretically the influence of RGO and Au NRs on the LED performance, and investigate the influence of substrate on the localized surface plasmon resonance (LSPR) coupling wavelength. Simulated results demonstrated that the LSPR peaks for Au NRs red shifted with increase in substrate refractive index, and the electric field along the x-y plane was mostly concentrated near the interface. RGO incorporation enhanced the emission of the QDs-LED. This may be attributed to improvement in conductivity and hole mobility in the hole transport layer and reduction in the energy barrier for injection of holes. After introduction of Au NRs, there was a significant enhancement in emission, and light extraction efficiency was enhanced about 10-fold.