An analytical approach for parameter extraction in linear and saturation regions of top and bottom contact organic transistors

摘要

This paper analyzes the behaviour of top contact (TC) and bottom contact (BC) OTFTs through charge drift model modifying in terms of device series resistance. Subsequently, the drain and the gate voltages take into account the potential drop across the respective contacts. The mobility is modified in terms of overdrive voltage (V-GS - V-T) and mobility enhancement factor as well. Additionally, the mathematical models are employed to extract the contact resistance including other parameters, such as, field dependent mobility, threshold voltage, mobility enhancement factor and drain current, separately for linear and saturation regimes. The model includes straightforward differential mathematics accounting of gate bias dependent contact resistance to evaluate the parameters analytically that too with single device only This resolves the complexity for realizing several devices with exactly same dimensions (except L) and moreover with same physical fabrication parameters. Besides this, the simulation is performed for four different TC and BC OTFTs using Atlas-Silvaco to comprehensively understand the device physics. Finally, the model is validated in terms of output characteristics and performance parameters against the experiment and simulation results. Analytically extracted mobility along with current for all four OTFTs is in a close harmony to the simulation results with an average error of 4 and 2.7 % in linear and saturation regions, respectively; whereas V-T is reasonably matched with 2 and 3 % average deviation.