Influence of Periodic Surface Nanopatterning Profiles on Series Resistance in Thin-Film Crystalline Silicon Heterojunction Solar Cells

摘要

In the frame of the development of thin crystalline silicon solar celltechnologies, surface nanopatterning of silicon is gaining importance. Itsimpact on the material quality is, however, not yet fully controlled.Weinvestigate here the influence of surface nanotexturing on the seriesresistance of a contacting scheme relevant for thin-film crystalline siliconheterojunction solar cells. Two dimensional periodic nanotextures arefabricated using a combination of nanoimprint lithography and either dry or wetetching, while random pyramid texturing is used for benchmarking. We comparethese texturing techniques in terms of their effect on the series resistance ofa solar cell through a study of the sheet resistance (Rsh ) and contactresistance (Rc) of its front layers, i.e., a sputtered transparent conductiveoxide and evaporated metal contacts. We have found by four-point probe and thetransfer length methods that dry-etched nanopatterns render the highest Rsh andRc values. Wet-etched nanopatterns, on the other hand, have less impact on Rcand render Rsh similar to that obtained from the nontextured case.