Structural stability of thermoelectric diffusion barriers: Experimental results and first principles calculations

Abstract

This study demonstrates the feasibility of producing a tantalum nitride (TaN) thin film as a diffusion barrier and buffer layer for p-type bismuth telluride [(Bi,Sb)2Te3] thermoelectric devices. A network of TaN with nitrogen (N) incorporation is structurally more stable on (Bi,Sb)2Te3 than the conventional Ni diffusion barrier because of less inter-diffusion and a greater likelihood of stoichiometry in the TaN/(Bi,Sb)2Te3 interface. The atomic inter-diffusion between the barrier layers and (Bi,Sb)2Te3 was evaluated in terms of interface adhesion energy using nanoscratching, and proved with first-principles calculations.