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In this paper we demonstrate a technique for improving the conversion efficiency in conventional silicon solar cells by using surface plasmon resonance (SPR) effects to harvest incident light energy over metal finger electrodes. According to three-dimensional finite-difference time-domain (3D-FDTD) analysis, incident light covering a broad bandwidth of the solar spectrum can be transmitted through metallic hole array structures. Although the light absorption region beneath the metal finger electrodes cannot generate a photocurrent, in this study, we employ the extraordinary transmission (EOT) phenomenon, due to SPR effects, to dramatically increase the degree of light harvesting below the metal electrodes and, thereby, improve the efficiency of the entire solar cell. Experimental data reveal that the excess photocurrent density was approximately 190% of the normal current density of a standard solar cell. Therefore, the negative effect of covering the absorption area with opaque metal finger electrodes can be minimized or eliminated completely by taking advantage of the SPR effect of the metal electrodes.

The use of metal catalyst to prepare nanostructures on semiconductor materials has attracted much attention because of the improved device performance. In this study, we employed the intruded Au nanocluster (INC) technique to prepare highly uniform, “atomic-scale” Au nanoclusters as highly active catalysts within Si wafers. The Au nanoclusters were readily prepared through the thermal coating of a Au film on a Si wafer followed by its removal using adhesive tape. Employing the Au nanoclusters as highly active catalysts allowed us to readily and rapidly prepare, at room temperature, unique Si nanostalactite (SNS) structures of ultrahigh density and very narrow diameter (ca. 10 nm). These SNS structures possessed superior light trapping capability relative to corresponding structures prepared using electroless metal deposition or self-assembled catalytic nanoparticle methods; in addition, the etching duration was much shorter. A field emission study revealed that the SNS structures, with their much narrower diameters, required a much lower turn-on voltage relative to that of corresponding Si nanowires.