Photovoltaic Properties of the Gallium Arsenide-PEDOT:PSS Interface

Abstract

This thesis reports studies on the interface between GaAs and the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in a planer Schottky diode architecture. The temperature dependence of the Schottky barrier height of the GaAs-PEDOT:PSS junction was found to be most accurately modeled using an interfacial layer model indicating that an oxide layer is forming at the interface. It has been found that chalcogenide passivation layers deposited from solution onto the GaAs surface did not improve device performance indicating that the passivation layer does not survive the PEDOT:PSS deposition. Small increases in pH of the PEDOT:PSS solution caused by the addition ofNH40H have been found to increase the fill factor of GaAs-PEDOT:PSS devices slightly, likely due to physical rearrangement of the polymer chains.