High-throughput characterization of the Seebeck coefficient of a-(Cr1 −xSix)1 −yOythin film materials libraries as verification of the extended thermopower formula

In a previous paper (Sonntag 2010 J. Phys.: Condens. Matter 22 235501) the classical thermopower formula has been argued to be incomplete, because it only takes into account the scattering properties of the carriers, but not the temperature dependence of the electrochemical potential μ caused by variation of the carrier density and/or band edge shift with temperature T. This argument is now checked experimentally by high-throughput measurements of the thermopower (Seebeck coefficient) S of a-(Cr(1-x)Si(x))(1-y)O(y) thin film materials libraries. The concentration dependences of S differ depending on whether the measurements are done with the complete film (where x ranges continuously from x≈0.3 to 0.8; y≈0.1-0.2) or with the separated pieces (each piece with another average value of x). These differences are especially large if, in addition, an oxygen gradient is present.