Enhanced performance of InGaN thin-film solar cells containining plasmonic and dielectric nanostructures

Abstract

We present Indium-rich InGaN thin-film solar cells containing plasmonic and dielectric nanostructures such as Ag and ITO nanopillars. Finite-difference time-domain (FDTD) simulations were carried out for solar cells containing these nanostructures on the back side and on the front side of the solar cells, and an improvement in the performance of the solar cells was compared for the different geometries and sizes of these nanostructures. In order to develop highefficiency InGaN solar cells, the indium content in the InGaN active layer needs to be increased in order to cover the large solar spectral range. Recently, several reports have demonstrated the growth of single-crystalline Indium-rich InGaN alloys without phase separation by controlling the growth temperature and the pressure. Our FDTD simulation results demonstrate that the Ag nanostructures on the back side of the solar cell lead to an enhanced surface plasmonbased scattering mostly for longer wavelengths of light including band edge of active material, while the ITO nanostructures on the front side lead to enhanced scattering of a middle wavelength range from 450 nm to 700 nm. Hence, a combination of Ag and ITO nanostructures leads to a significant broadband absorption enhancement in the active-medium of the solar cells which in turn leads to a significant enhancement (~ 25 %) in the short circuit current density (Jsc) of these solar cells.