Light trapping effect of heterojunction AlGaN nanowires adsorbed by metal nanoparticles

Abstract To improve the photoelectric conversion capability, the models of heterojunction AlGaN nanowire (NW) array decorated with metal (Ag, Al, Au and Pt) nanoparticles (NPs) were constructed using the finite difference time domain (FDTD) method. The optical performance of heterojunction AlGaN NW arrays are affected by some factors, such as the number and thickness of different Al components, as well as the radius and spacing of NPs. Heterojunction AlGaN NW arrays containing low-Al component have high light absorption in the ultraviolet band, and the adsorption of Al NPs can especially increase the light absorption. What’s more, the adsorption of metal particles can improve the light binding capacity only in appropriate size and spacing. The results show that the 5-layer heterojunction AlGaN NWs adsorbed by Al NPs have a light absorption of 98.26% with a wavelength of 335.69 nm, and the quantum efficiency can reach 43.45% with a wavelength of 200 nm. The method in this paper provides the basis for the preparation of heterojunction AlGaN NW array photocathode, which can effectively improve the light trapping effect.