Plasmonic metasurface for light absorption enhancement in GaAs thin film

Using the plasmonic metasurface, we have designed a highly efficient solar ray absorber by tailoring the thickness of the metallic arrays. The geometric-dependent local surface plasmon and concomitant local enhanced electric field are excited, leading to the decay of internal plasmon into energetic electron-hole pair. The architectures of the metasurface deposited on and embedded in the GaAs film have been investigated to exploit the potential of the surface plasmonic. The peak absorbance of the deposited one increases monotonically from about 0.52 at the metasurface thickness of 5 nm to 0.86 at that of 60 nm. While the absorption intensity for the embedded one reaches to 0.92 at the metasurface thickness of 10 nm and further increases to near unity as thickness increases to 30 and 60 nm. The average absorption in the whole spectrum shows that the efficiency of the embedded one is superior to the deposited one. This design is of high economic competitiveness for photovoltaic applications and can be used in complex material system for multifunction including energy harvest and sensor device.