In this work we report the synthesis of rGO from Sri Lankan vein Graphite, their deposition on patterned indium tin oxide (ITO) substrates as thin films via two different approaches, and the measurement of photocurrents using a Keithley 485 Autoranging picoammeter at 3.82 mW/cm² and 141.0 mW/cm² irradiance respectively. Our detailed analysis of data reveals that photocurrent values for specific locations/regions of the thin film can be extracted for further analysis. As indicated in the diagram we identify the contributions from specific regions to the photocurrent measured. The technique can be adopted to reveal the microscopic variations of photocurrents of specific regions of a thin film that can be utilized in the investigations of thin film devices to be used as photodetectors, photovoltaic cells, and optoelectronic sensors. In the films investigated we demonstrate this by determining the significant variations in photocurrents within the single thin film itself. Moreover, the Raman spectroscopic data are correlated with the photocurrent data of specific regions of a film to elucidate the structure-photocurrent relationships in photosensitive thin films.

Raw photocurrent values (in pA) were observed for the rGO thin films prepared and difference-photocurrent values (Δi) can be obtained for different regions of the thin films indicating microscopic relative photocurrent generation at different regions of the film upon photo-excitation.

Neranga Abeyasinghe

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