Hamburg 2001 – scientific programme

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HL: Halbleiterphysik

HL 24: Poster II

HL 24.65: Poster

Thursday, March 29, 2001, 10:30–19:00, Rang S\ 3

Experimental characterization and simulation of P3OT-based field effect devices — •Susanne Scheinert¹ and Gernot Paasch² — ¹TU Ilmenau — ²IFW Dresden

Thin film transistors and MOS capacitors with P3OT as the active layer have been prepared by spin coating under different processing conditions. Unintentional high doping by oxygen requires layers of only ≈10nm thickness. With an oxide thickness of 50nm an operating voltage less than 10V has been achieved. The devices have been characterized by the quasi static capacitance, impedance measurements and transfer and output characteristics. The data are analyzed by using besides estimates with analytical expressions also 2D simulations and an appropriate equivalent circuit model for the capacitor. As in PPV based devices [1] current and capacitance measurements show hysteresis effects which can be described by a variation of an interface charge of the order of 10¹²cm⁻² and which are connected with the oxidation of the polymer. In spite of the extremely small thickness of the layer detailed information on both concentration and mobilitiy can be extracted separately for the bulk and the accumulation layer. The subthreshold slope could be reduced to S≈200mV/dec. Unexpectedly the mobility shows an extreme anisotropy of about 10³ indicating a regularity of the arrangement of the polymer chains even in the spin coating deposition of the layer.

[1] S. Scheinert, G. Paasch, S. Pohlmann, H.-H. Hörhold, R. Stockmann, Solid-State Electronics 44 (2000) 845