Study of Au nanoparticles adsorbed on InGaAs/InP thin films to improve optical absorption properties in the near-infrared band

In this paper, we use FDTD Solutions software to construct the light-absorption model of InGaAs/InP thin films modified by Au nanoparticles. And the effects of Au nanoparticles on the light-absorption performance of thin films in the near-infrared wavelengths are investigated in terms of nanoparticle position, array period, and particle radius. And for the 1064 nm wavelength band, we obtain the optimal structural model. It has been shown that nanoparticle modification on the front side of the emission layer is the most effective in promoting light absorption; the resonance peaks formed by the surface plasmon excitations can greatly affect the light-absorption rate of Au nanoparticles adsorbed on the film, and the position of the absorption peaks can be changed by altering the array period and particle radius to achieve the enhancement of the film's absorption of light in a specific wavelength band. For the 1064 nm band, we obtain the best model, when the radius of Au NPs in the emission layer is 25 nm, and the model absorption with an array period of 150 nm is up to 84.85%, and the quantum efficiency is improved by one-third compared with the thin film. It provides a certain reference for the design of photocathode in the near-infrared band.