Estimation of Depletion Layer Thickness in PEDOT-PSS Films

This paper presents a simple method to prove the existence of rectifying contact between PEDOT-PSS and Tin. An attempt was made to separate the contact resistance from the bulk resistance and found that the contact resistance offered was about 5.16 times greater than the actual film resistance. Investigations were also made on PEDOT-PSS films making contact with Tin and found that the depletion layer capacitance offered at the metal-semiconductor interface was about 20 nF at low frequency. The Thickness of the depletion region at the interfacial region was calculated to be about 388 nm. The findings from this work infer that the order of contact resistance is significantly high and needs to be eliminated when used as a device. Also, the existence of large junction capacitance at the interface of PEDOT-PSS and Tin makes it a suitable material to be used as supercapacitors.