The Electrical Properties of Plasma-Deposited Thin Films Derived from Pelargonium graveolens

Inherently volatile at atmospheric pressure and room temperature, plant-derived precursors present an interesting human-health-friendly precursor for the chemical vapour deposition of thin films. The electrical properties of films derived from Pelargonium graveolens (geranium) were investigated in metal-insulator-metal (MIM) structures. Thin polymer-like films were deposited using plasma-enhanced synthesis under various plasma input power. The J-V characteristics of thus-fabricated MIM were then studied in order to determine the direct current (DC) conduction mechanism of the plasma polymer layers. It was found that the capacitance of the plasma-deposited films decreases at low frequencies (C approximate to 10(-11)) and remains at a relatively constant value (C approximate to 10(-10)) at high frequencies. These films also have a low dielectric constant across a wide range of frequencies that decreases as the input RF power increases. The conductivity was determined to be around 10(-16)-10(-17) Omega(-1) m(-1), which is typical for insulating materials. The Richardson-Schottky mechanism might dominate charge transport in the higher field region for geranium thin films.