We report the electrical properties and charge transport behavior of an electrodeposited, vacuum-annealed (100 °C) pure Cu2O and air-annealed (at 300 °C) Cu–O (mixed phase of Cu2O and CuO) films in the device geometry of ITO/Cu2O/Al and ITO/Cu–O/Al. An intermediate poly(3-hexylthiophene) (P3HT) layer was deposited by spin coating to fabricate devices with the structures ITO/Cu2O/P3HT/Al and ITO/Cu–O/P3HT/Al. The incorporation of P3HT significantly alters the device characteristics from ohmic to Schottky-type behavior. The device ITO/Cu2O/P3HT/Al shows better I–V characteristics compared to ITO/Cu–O/P3HT/Al in terms of its lower leakage or reverse saturation current (of the order ∼10–7 mA). Furthermore, the Schottky barrier height (φB) at P3HT/Al for both devices is of the same order ∼0.9 eV. Impedance Spectroscopy (IS) measurements were performed on all the devices in the frequency range of 40 Hz–100 MHz to understand the device characteristics and AC charge transport phenomenon. An equivalent circuit model with two RQ parallel (Q: constant phase element) components in series best fits the IS data, highlighting the separate roles of bulk and interfacial effects. Mott–Schottky analysis confirms p-type behavior for Cu2O films, whereas Cu–O exhibits n-type characteristics arising due to oxygen vacancies. This work demonstrates the potential of Cu2O/P3HT interface engineering for optoelectronic device applications.
Patel et al. (Wed,) studied this question.