Realization of specific localized surface plasmon resonance in Au-modified Ni nanoplasmonics for efficient detection

Monometallic nanostructures have gained tremendous research attentions owing to the ability of supporting surface plasmons and improving devices performance. However, the relatively inflexible localized surface plasmon resonance (LSPR) absorption peaks restrict the further development of monometallic plasmonics and relevant applications. Herein, the bimetallic Au-Ni nanoparticles (NPs) with an ~ 325 nm LSPR absorption peak were fabricated and decorated on polar GaN microwire (MW) array PDs via thin film thermal annealing approach. Compared with monometallic Au and Ni NPs, the bimetallic Au-Ni NPs can not only modulate LSPR absorption peak but also enhance absorptivity. Moreover, the bimetallic NPs/GaN MW array PDs demonstrated the maximum increase in responsivity than bare GaN under the resonance wavelength of 325 nm. The improvement in bimetallic NPs devices is correlated with the stronger light absorption, scattering and hot electron transfer at the GaN interface. This work presents a simply valid method for preparing the bimetallic Au-Ni NPs with tunable LSPR absorption peak, which can be helpful for realizing the energy-efficient optoelectronic device applications in most functional fields.