Abstract:

In this study, semiconductor metal oxide ZnO compound was grown on glass/ITO substrate by electrochemical deposition technique. Later on, C24H12 organic semiconductor layer was deposited on glass/ITO/ZnO junction by thermal evaporation method and glass/ITO/ZnO/C24H12 multi heterojunction was fabricated. Surface analyses of produced layers was performed by Scanning electron microscopy (SEM) and it is seen that surface morphology of ZnO and C24H12 has nanoflake-nanorod structures and, nanowire structure, respectively. In addition, the elemental distribution of the ZnO layer was examined by Energy dispersive X-ray spectroscopy (EDS), and it was observed that Zn and O elements exhibited a homogeneous distribution within the layer. The electrical properties of Ag/ITO/ZnO/C24H12/Ag multi heterojunction were characterized under dark and 100mW/cm2 light intensity in the range of ±1.5V application potential. In the dark environment, series resistance (Rs), diode ideality factor (n), barrier height (∅b), reverse saturation current (I0) were ≈104Ω, 7.5-6.5, 0.647 eV and 5.7x10-7 A, respectively, while under 100mW/cm2 light intensity, these values were found to be ≈ 103Ω, 6.5-1.3, 0.914 eV and 1. 9x10-11 A, respectively. The photocurrent (Iph), photosensitivity (R) and photosensitivity (S) values, which are important parameters for the photoconductivity mechanism of the multi heterojunction, were determined at different voltage values under forward bias. In addition, the photovoltaic parameters of the multi heterojunction were calculated and the fill factor FF was found to be 0.56. As a result, it was observed that the Ag/ITO/ZnO/C24H12/Ag multi-heterojunction exhibited photodiode and photovoltaic behaviour.

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