Enhancement of Light Absorption with Whispering Gallery Modes in Weakly Tapered Silicon Nanowire Solar Cells

Abstract

Silicon nanowire (SiNW) solar cells with optical resonances are promising high efficiency photovoltaic cells that significantly increase optical absorption with elongated the light trapping path. The taper of SiNW induces total internal reflection of incident light, forming multiple whispering gallery modes (WGMs) and leading broadband light absorption. Here, we analyzed strong WGMs formed in weakly tapered SiNW using optical simulations, and evaluated their impact on the improvement of solar cell characteristics. The fabricated tapered SiNW solar cell shows a 1.6-fold increase in short-circuit current (JSC) compared to that of cylindrical counterpart, with only simple geometrical change.