Vertical Nanotube QDLED Anode for Active Matrix Drive Current
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Solution Overview
Problem
Quantum dot light emitting diodes (QDLEDs) require high drive current/power, making it difficult to drive them using conventional amorphous Si thin-film transistors as in current liquid crystal display (LCD) active matrix displays.
Innovation Solution
A vertically integrated device structure using a semiconducting nanotube thin film as the anode for QDLEDs, where the nanotube film is transparent and its conductivity is tuned by an embedded local gate to control the drive current, allowing for effective pixel control and integration into an active matrix display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional amorphous Si thin-film transistors are used to drive QDLEDs, then the device structure is simple and manufacturing is easier, but the drive current is insufficient due to low carrier mobility
Solution Approach 1:
The patent transitions from a planar transistor structure to a vertically integrated three-dimensional structure. The nanotube film is stacked above the gate electrode with gate dielectric material in between, creating a vertical field effect transistor configuration that provides higher drive current while maintaining manufacturability through sequential layer deposition
Solution Approach 2:
The patent employs a composite structure combining semiconducting nanotube thin film (high mobility material) with gate dielectric material and gate electrode. This composite vertical structure leverages the high carrier mobility of nanotubes to achieve sufficient drive current for QDLEDs, overcoming the limitations of conventional amorphous Si TFTs
2Power
If the nanotube film conductivity is increased to provide sufficient drive current, then the light emission control is improved, but the transparency of the nanotube film may be reduced
Solution Approach 1:
The patent applies local quality by creating spatially differentiated regions: the nanotube film region provides electrical conduction for drive current, while the gate dielectric material region provides electrical isolation. This local functional differentiation allows the nanotube film to be optimized for transparency in the light path while maintaining sufficient conductivity when activated by the gate field
Solution Approach 2:
The patent segments the electrical conduction function from the light transmission function by introducing the gate dielectric material as a separate layer. The nanotube film is segmented into conductive channels controlled by the gate, allowing independent optimization of transparency and conductivity in different operational states
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 high mobility of nanotube thin films provides sufficient drive current for QDLEDs, enabling easier integration into active matrix displays and allowing for efficient light emission control by switching the nanotube film between conductive and insulating states.
Implementation Method 1
the conductivity of the nanotube film is tuned by an embedded local gate to control the drive current
Implementation Method 2
An applied electric field causes electrons and holes to move into the quantum dot layer, where they are captured in the quantum dot and recombine, thereby emitting photons
Data Source
AI summary
A technique relates to a vertical device. A gate is embedded in a transparent substrate. A gate dielectric material is disposed on the gate. A nanotube film is disposed on the gate dielectric material. A quantum dot light emitting diode is disposed on a portion of the nanotube film.