Organic Thin-Film Transistor Surface Design for Uniform High Mobility
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Solution Overview
Problem
Existing organic thin film transistors face challenges in achieving high mobility and uniformity of organic semiconductor films due to the trade-off between solubility and crystallinity, with conventional methods struggling to control drying and crystal growth effectively.
Innovation Solution
A bottom-gate and top-contact organic thin film transistor configuration is employed, utilizing a boehmite-treated alumina gate insulating film with a self-assembled monolayer film to enhance water repellency and align organic semiconductor molecules, allowing for controlled crystal growth and high mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the solubility of organic semiconductor material in solvent is increased to improve film uniformity, then the mobility of the organic semiconductor film deteriorates
Solution Approach 1:
The invention applies local quality by treating only the surface of the gate insulating film with boehmite to create a specific surface structure (fine pores with 1-10 nm diameter) that selectively affects solvent evaporation and crystal growth. This localized surface treatment enables uniform film formation without requiring high material solubility, thereby maintaining high mobility while achieving good uniformity.
Solution Approach 2:
The invention changes the physical parameters of the gate insulating film surface by forming boehmite with specific pore size (1-10 nm) and surface area (50-500 m²/g). These parameter changes control the drying process of the coating liquid, enabling uniform crystal growth at lower material concentrations, thus resolving the contradiction between uniformity and mobility.
2Speed
If the drying speed of coating liquid is increased to improve crystal growth control, then the uniformity of organic semiconductor film deteriorates
Solution Approach 1:
The boehmite surface treatment creates localized fine pores that control solvent evaporation rate. The specific pore structure (1-10 nm diameter) provides controlled local drying environments that enable uniform crystal growth across the entire film, preventing the uniformity deterioration that would result from rapid overall drying.
Solution Approach 2:
The boehmite layer acts as an intermediary between the gate insulating film and the organic semiconductor coating liquid. It mediates the drying process by providing a controlled evaporation environment through its fine pore structure, enabling uniform crystal growth even at moderate drying speeds.
3Speed
If the solubility of organic semiconductor material is decreased to improve mobility, then the uniformity of organic semiconductor film deteriorates
Solution Approach 1:
The invention changes the surface parameters of the gate insulating film (pore size, surface area) to compensate for low material solubility. The boehmite treatment creates a surface that controls solvent evaporation and crystal growth, enabling uniform film formation from low-concentration solutions, thus achieving both high mobility and uniformity.
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 configuration results in an organic thin film transistor with improved uniformity and mobility of the organic semiconductor film, overcoming the limitations of conventional approaches by focusing on surface structure rather than material solubility.
Implementation Method 1
it has been exemplified in the existing invention that the uniformity of the organic semiconductor film can be improved by matching the growth speed of the crystal with the drying speed of the coating liquid
Implementation Method 2
a self-assembled monolayer film (a SAM film) is formed on a surface of the gate insulating film, which is the surface, to be formed, of the organic semiconductor film
Data Source
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AI summary
An object of the present invention is to provide an organic thin film transistor having an organic semiconductor film having good uniformity and high mobility, and a method for manufacturing the organic thin film transistor. The organic thin film transistor has a gate electrode, a gate insulating film that is provided to cover the gate electrode, a self-assembled monolayer film that is provided on the surface of the gate insulating film, and an organic semiconductor film, a source electrode, and a drain electrode, which are provided on a side of the self-assembled monolayer film opposite to the gate insulating film, where the gate insulating film is alumina and the surface thereof has an uneven structure due to a boehmite treatment, whereby the object is achieved.