The resistance of a pn junction in the dark (also called the shunt resistance) is well documented and can be used as a starting point to discuss the Si resistances observed in this study. The slope of the dc current-voltage response defines the resistance, R, through 𝑅 = 𝑑𝑉 𝑑𝐼 ⁄ , where V and I are the voltage and current, respectively. This resistance, found through dc characteristics, is also defined to be the ac resistance, determined with EIS. In forward bias, majority carriers flow through the junction and there is a small resistance associated with this process. As the applied voltages move the device towards depletion, the observed resistance increases and prevents majority carriers from passing through the junction. For ideal diodes, the resistance in this region is infinite, as the slope of the current-voltage response is zero. For non-ideal diodes, a small leakage current of minority carriers exists in depletion.