Thin Film Transistor Lewis Acid Electron Withdrawing Layer
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Solution Overview
Problem
Thin film transistors in flat panel displays, particularly organic electroluminescent displays, face high contact resistance between source and drain electrodes and the semiconductor layer, leading to deteriorated device characteristics and increased power consumption.
Innovation Solution
Incorporating an electron withdrawing layer composed of a Lewis acid compound between the organic semiconductor layer and the source and drain electrodes, which facilitates charge accumulation and reduces contact resistance by forming a channel doping effect, thereby enhancing carrier injection and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low work function metal is used for source and drain electrodes to enable smooth charge movement, then charge mobility is improved, but contact resistance between the electrode and semiconductor layer increases
Solution Approach 1:
An electron withdrawing layer composed of a Lewis acid compound is introduced as an intermediary between the low work function metal electrode and the organic semiconductor layer. This intermediate layer facilitates charge transfer by accepting electrons from the semiconductor and transferring them to the electrode, thereby reducing contact resistance while maintaining the low work function benefit for charge mobility.
Solution Approach 2:
The invention changes the chemical and electrical parameters at the electrode-semiconductor interface by introducing a layer with specific electron withdrawing properties. The Lewis acid compound creates favorable energy level alignment and enhances charge extraction efficiency, transforming the interface characteristics to achieve both low contact resistance and high charge mobility.
2Adaptability or versatility
If organic semiconductor layers are used to enable low temperature formation on plastic substrates, then substrate flexibility is improved, but contact resistance in the contact region increases
Solution Approach 1:
The electron withdrawing layer acts as a mediator that compensates for the inherent high contact resistance of organic semiconductors. By positioning this layer at the critical contact region, it enhances charge extraction from the organic semiconductor to the electrode without requiring high temperature processing, thus maintaining compatibility with plastic substrates while reducing contact resistance.
Solution Approach 2:
The invention creates a composite structure at the electrode interface combining the low work function metal, the Lewis acid compound-based electron withdrawing layer, and the organic semiconductor layer. This composite material system leverages the advantages of each component: the metal provides low work function, the Lewis acid layer provides efficient charge extraction, and the organic layer provides flexibility and low temperature processing capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively decreases contact resistance and increases charge mobility, resulting in improved reliability and reduced power consumption for thin film transistors and flat panel displays.
Implementation Method 1
an electron withdrawing layer comprising a Lewis acid compound arranged between the organic semiconductor layer and at least one of source and drain electrodes
Data Source
AI summary
Provided are a thin film transistor and an organic electrolumienscent display including the same. The organic electroluminescent display includes: a gate electrode; source and drain electrodes that are insulated from the gate electrode; an organic semiconductor layer that is insulated from the gate electrode and electrically connected to the source and drain electrodes; an insulating layer that insulates the gate electrode from the source and drain electrodes or the organic semiconductor layer; and an electron withdrawing layer composed of a Lewis acid compound formed between the source and drain electrodes and the organic semiconductor layer. Charges can easily accumulate so that a channel doping effect occurs in the semiconductor layer, thus preventing the formation of an energy barrier and increasing the number of carriers that are injected into a channel. As a result, a TFT having a low contact resistance, an large number of injected carriers, and good charge mobility can be obtained. A flat panel display including the TFT is reliable and has low power consumption.