Organic Thin Film Transistor with Carbon Nanotube Composite Channel
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Solution Overview
Problem
Organic thin film transistors (TFTs) have inferior charge mobility and switching speed compared to polycrystalline silicon TFTs, limiting their application in voltage-drive flexible flat panel displays that require high performance.
Innovation Solution
Incorporating carbon nanotubes (CNTs) with an organic semiconductor material in the channel layer of the TFT, either as a homogeneous or non-homogeneous mixture, and using a combination of layer structures and deposition processes such as spin coating, ink-jet printing, and sintering to enhance charge mobility and switching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an organic semiconductor layer is used in the TFT channel, then the fabrication cost is reduced and compatibility with low-temperature processes is improved, but the charge mobility and switching speed are significantly inferior to polycrystalline silicon TFTs
Solution Approach 1:
The patent combines carbon nanotubes with organic semiconductor materials to form a composite semiconductor layer. This composite structure leverages the high charge mobility of carbon nanotubes while maintaining the low-cost, low-temperature fabrication advantages of organic materials, thereby resolving the contradiction between ease of manufacture and charge mobility.
Solution Approach 2:
The patent modifies the semiconductor layer by incorporating carbon nanotubes at specific concentrations and configurations, changing the physical and electrical parameters of the organic semiconductor material to achieve higher charge mobility while maintaining compatibility with low-temperature processing.
2Temperature
If an organic semiconductor layer is used in the TFT channel, then the fabrication process can be performed at low temperatures, but the switching speed is insufficient for high-performance display applications
Solution Approach 1:
By creating a composite of carbon nanotubes and organic semiconductor materials, the patent achieves high switching speed comparable to polycrystalline silicon while maintaining the low-temperature processing capability of organic materials.
Solution Approach 2:
The patent introduces carbon nanotubes as discrete conductive elements within the organic semiconductor matrix, creating local high-mobility pathways that enhance overall switching speed without compromising the low-temperature processing characteristics of the bulk organic material.
3Reliability
If carbon nanotubes are incorporated into the organic semiconductor layer, then charge mobility is enhanced to greater than 3.3 cm2/V·sec, but the device complexity and fabrication process complexity increase
Solution Approach 1:
The patent incorporates carbon nanotubes into the organic semiconductor layer during the initial deposition process, performing the enhancement action in advance rather than as a separate post-processing step, thereby reducing overall fabrication complexity.
Solution Approach 2:
The patent merges the carbon nanotube incorporation step with the organic semiconductor layer deposition process, combining multiple functions into a single fabrication step to reduce process complexity while achieving enhanced charge mobility.
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 integration of CNTs with organic semiconductor materials significantly improves charge mobility to greater than 3.3 cm2/V·sec and on/off ratio to greater than 1×109, enabling high-speed operation suitable for advanced display devices.
Implementation Method 1
Carbon nanotubes (CNTs) have a low work function and exhibit a high electric field concentration effect because of its high aspect ratio
Implementation Method 2
a pentacene thin layer is formed using a thermal evaporation process or a solution-based process such as a spin coating process
Implementation Method 3
a solution-based process such as a spin coating process
Implementation Method 4
the organic layer is sintered to form an organic semiconductor layer
Data Source
AI summary
An organic thin film transistor (TFT) and a method of fabricating the same are provided. In the method, an organic semiconductor layer is formed by mixing carbon nanotubes with an organic semiconductor material or coating the organic semiconductor material on a carbon nanotube layer. The resulting organic semiconductor layer has enhanced charge mobility and switching speed owing to the carbon nanotubes' high electric conductivity and charge mobility.