Chemical and Electrochemical Deposition of Ag onto Si for Fabrication of Si Nanowires and the Seebeck Effect Characterization

In this work, vertically aligned porous Si nanowire (SiNW) arrays were successfully fabricated on two sides of an n-type Si wafer substrate. Ag nanoparticles (NPs) were first deposited onto the Si substrate via two different deposition methods, chemically and electrically (cyclic voltammetry), afterwards the metal assisted chemical etching (MaCE) technique was implemented to fabricate the SiNWs. The thermoelectric property of the SiNWs/Si/SiNWs structure was characterized by the Seebeck coefficient (S) which was measured at room temperature. Our results show a higher S when Ag NPs were electrodeposited onto the Si wafer piece compared to chemical deposition. The S enhancement is times and times in comparison to that of bulk Si and Ag chemical deposition samples, respectively. The electrodeposition created a strong adhesion between the Ag NPs and Si substrate which ensured a more uniform dispersed SiNWs producing a higher S. The improved thermoelectric performance coupled with electrodeposition of Ag indicates that the SiNWs/Si/SiNWs structure is an excellent candidate for the application in high-performance thermoelectric devices.