Preparation and characterization of an vertical organic field-effect transistor

Author(s)

Gabriel Leonardo Nogueira

• Document type: Master's Dissertation
• Press: Bauru. 2016-11-10.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências. Bauru
• Defense date: 2016-08-26
• Advisor: Neri Alves

Abstract

A way of circumvent the limitations of conventional organic field-effect transistor (OFET), is by using the vertical organic field-effect transistor (VOFET). In this structure, with layers stacked vertically, the semiconductor is sandwiched between source and drain electrodes, where the channel length is determined by the thickness of the semiconductor film. In this study, we report a VOFET with Al and Al2O3 (obtained by anodization) as electrode and dielectric of gate, respectively. The semiconductor film was obtained by spin-coating of the P3HT in chloroform. We obtained the source and drain electrodes by vacuum thermal evaporation. The use of Al and Au as source and drain, respectively, enabled the investigation of the two devices contained in the VOFET (MIM capacitor, Schottky diode and MIS capacitor). Important parameters were determinate, as dielectric capacitance (~265 nF/cm2), charrier density and mobility of P3HT (NA = 9,2 x 1016 cm-3 e μ = 1,5x10-4 cm2V-1s-1), etc. To use Sn as source electrode, the film (by evaporation) was investigated by measurements of resistance and capacitance, combined with morphological analysis by AFM. We observed that the addiction of PMMA layer on Al2O3 improves the performance of VOFET. For VOFET obtained by using Al2O3/PMMA (20 nm/14 nm) as dielectric layer, with Sn and Al as source and drain, respectively, were calculate the values of current density (Jeff = 7x10-3 mA/cm2), threshold voltage and electric field (VTH = -8V e ETH = 330 MV/m). Thereat, we obtained a VOFET by evaporation of a thin film of Sn as perforated source electrode. (AU)

• FAPESP's process: 13/26973-5 - Preparation and characterization of an organic field effect transistor using a vertical architecture
• Grantee: Gabriel Leonardo Nogueira
• Support Opportunities: Scholarships in Brazil - Master