Figure 3 (a) Schematic diagram of the device for contact resistance measurement. (b) IV curves corresponding to c-Si(p)/a-Si:H(i)/MoOx/ICO/Ag stacks with different electrode diameters. The arrow direction represents the electrode diameter decreasing.
Total resistance in ECSM can be expressed as:
RT= Rs+ Rc+ R0 (1)
where RT is the total series resistance,Rs the extended resistance,Rc the contact resistance, andR0 the residual resistance.RT can be obtained by fitting the experimentalI -V curve according to equation (2), where V is the applied voltage, I the current, n the ideal factor,q the electron charge, k the Boltzmann constant, andT the absolute temperature. Rs can be calculated from equation (3), where ρ and t are the resistivity and thickness of the Si substrate, respectively, d is the diameter of the circular electrode. ρc is the specific contact resistivity and can be obtained according to equation (4)[33].
(2)
(3)
(4)