Organic Thin Film Transistor Ohmic Contact via Intermediary Layer
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Solution Overview
Problem
Achieving an ohmic contact and enhancing the adhesive force between organic semiconductor layers and inorganic source/drain electrodes in thin film transistors is challenging due to differences in work function and material compatibility.
Innovation Solution
Incorporating an ohmic contact layer with a work function between that of the source/drain electrodes and the organic semiconductor layer, and using hole transporting compounds or materials with a hole transporting unit to facilitate effective contact and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If source/drain electrodes are formed of inorganic material and organic semiconductor layer is formed of organic material, then low temperature manufacturing is enabled, but adhesive force between source/drain electrodes and organic semiconductor layer is weak
Solution Approach 1:
An adhesive layer is introduced as an intermediary between the inorganic source/drain electrodes and the organic semiconductor layer. This adhesive layer comprises a material with work function between that of the inorganic electrode and organic semiconductor, enabling both strong adhesion to the inorganic electrode and good electrical contact with the organic semiconductor, thereby resolving the weak adhesive force problem while maintaining low temperature manufacturing
Solution Approach 2:
The contact structure uses composite material composition: inorganic source/drain electrode + adhesive layer (intermediate material) + organic semiconductor layer. This composite structure combines the advantages of inorganic materials (low temperature processing compatibility) with improved interfacial adhesion and electrical contact properties
2Temperature
If source/drain electrodes are formed of inorganic material, then low temperature manufacturing is enabled, but ohmic contact with organic semiconductor layer is difficult to achieve
Solution Approach 1:
The adhesive layer serves as an electrical intermediary that facilitates ohmic contact between the inorganic source/drain electrode and organic semiconductor layer. By selecting material with intermediate work function, it reduces the Schottky barrier height at the interface, enabling efficient charge carrier injection and achieving ohmic contact characteristics
Solution Approach 2:
The work function parameter of the contact interface is optimized by introducing the adhesive layer with specific work function value between the inorganic electrode and organic semiconductor. This parameter adjustment enables the system to achieve both low temperature processing compatibility and reliable ohmic contact
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
This approach enables reliable ohmic contact and increased adhesive force, improving the electrical properties and lifespan of thin film transistors, thereby enhancing the performance and reliability of flat panel displays.
Implementation Method 1
an ohmic contact layer that is interposed between the source and drain electrodes and the organic semiconductor, and that comprises a material that has a work function that is greater than a work function of a material of the source and drain electrodes and less than a work function of a material of the organic semiconductor layer
Data Source
AI summary
A thin film transistor includes: a gate electrode; source and drain electrodes insulated from the gate electrode; an organic semiconductor layer that is insulated from the gate electrode and is 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 ohmic contact layer that is interposed between the source/drain electrodes and the organic semiconductor and contains a compound having a hole transporting unit. By providing the ohmic contact layer, the ohmic contact between source/drain electrodes and the organic semiconductor layer can be effectively achieved and the adhesive force between the source/drain electrodes and the organic semiconductor layer is increased. In addition, a flat panel display having improved reliability can be obtained using the thin film transistor.