Percolative Effects on Noise in Pentacene Transistors

TL;DR

This study investigates 1/f noise in pentacene transistors across various thicknesses, revealing that noise behavior is governed by percolative effects related to grain boundary structures, with mobility fluctuations being the primary source.

Contribution

It demonstrates that noise in pentacene transistors is dominated by percolative effects and mobility fluctuations, extending understanding to ultra-thin films and linking noise parameters to grain boundary structures.

Findings

Noise remains 1/f across all thicknesses.

Hooge's parameter inversely related to conductivity.

Percolative effects explain noise characteristics.

Abstract

The 1/f noise in pentacene thin film transistors has been measured as a function of device thickness from well above the effective conduction channel thickness to only two conducting layers. Over the entire thickness range, the spectral noise form is 1/f, and the noise parameter varies as (gate voltage)-1, confirming that the noise is due to mobility fluctuations, even in the thinnest films. Hooge's parameter varies as an inverse power-law with conductivity for all film thicknesses. The magnitude and transport characteristics of the spectral noise are well explained in terms of percolative effects arising from the grain boundary structure.