Investigation of pectin-based thin film as an active layer for resistive random access memory
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Date
2019-05
Authors
Isamuddin Bin Mohamed Iqubal
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Abstract
Electronic-waste (e-waste), which mostly contains toxic materials such as lead, mercury, beryllium and many more that is not easily to decompose is a problem that can give threat to human health and environment. Hence, an ideal of using natural-based thin film for electronic applications is suggested in this research. In this research, the effects of Pectin powder in the range of 1 mg, 2 mg, 3 mg and 4 mg and the effect of different drying temperatures (120°C, 140°C, 160°C and 180°C) on the formation of Pectin-based thin film were studied. Pectin-based thin film was fabricated by mixing Pectin powder with deionized water to form a precursor solution, then drop-casting the solution on top of an Indium tin oxide (ITO)-coated polyethene terephthalate (PET) substrate. Then, drop-casted sample was dried in oven for 2 hours to form a Pectin-based thin film and characterized by using several characterization techniques. From FESEM, Pectin precursor with higher drying temperature (160°C and 180°C) shows a uniform and flat structure when coated on ITO/PET substrate, while lower drying temperature (120°C and 140°C) shows a granular and uneven structure when coated on ITO/PET substrate. It is further supported by the AFM topography result, which shows the evolution from a granular and uneven structure to a uniform and flat structure as the drying temperature increases from 120°C to 180°C. From fingerprint region in FTIR, higher concentration of Pectin solution has higher intensity, which indicates that the dipole moment strength of the chemical functional groups of –COO-, C-O-C, C-O, and C-H increases as the concentration of pectin precursor increase. From Mprobe 20 UVVisSR thin film, the lowest and the highest values obtained for the thickness of Pectin-based thin film are 159.2 nm (at drying temperature of 180°C with concentration of 4 mg) and 405.5 nm (at drying temperature of 120°C with concentration of 1 mg). By using the Beer’s Lambert equation, the lowest and highest values obtained for direct energy bandgap of Pectin-based thin film are 1.512 eV (at drying temperature of 140°C with concentration of 1 mg) and 1.896 eV (at drying temperature of 180°C with concentration of 4 mg). The lowest and highest values obtained for indirect energy bandgap of Pectin-based thin film are 1.254 eV (at drying temperature of 120°C with concentration of 4 mg) and 2.011 eV (at drying temperature of 180°C with concentration of 2 mg). This indicate that the Pectin layer shows a conductive bandgap for both direct and indirect bandgap when it is coated on top of the ITO/PET substrate.