Organic Transistor Current Amplification via Diode Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic transistor devices, such as metal-base organic transistors (MBOTs), face challenges in achieving high current amplification and on/off ratios necessary for driving organic EL displays, particularly due to difficulties in forming intermediate electrodes and requiring heat treatment for oxide layer formation.
Innovation Solution
A current-amplifying transistor device with a diode structure comprising p-type and n-type organic semiconductor layers between the emitter and collector electrodes, which allows for large-current amplification and high on/off ratios without the need for heat treatment, using materials like metal phthalocyanine and fullerene, and incorporating a lithium fluoride layer for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a vertical-type transistor structure is used to obtain large current in low voltage range, then current amplification capability is improved, but device complexity increases due to difficulty in forming intermediate electrodes
Solution Approach 1:
The transistor is divided into three distinct functional layers: emitter layer, base layer, and collector layer. Each layer is formed separately through sequential vapor deposition processes, simplifying the formation of intermediate structures compared to conventional vertical transistors that require complex intermediate electrode patterning
Solution Approach 2:
A lithium fluoride layer is introduced as an intermediary between the base layer and collector layer to facilitate charge transport and improve interface characteristics, eliminating the need for complex intermediate electrodes while maintaining current amplification capability
2Reliability
If heat treatment is applied to form oxide layer for stable performance, then reliability is improved, but manufacturing process complexity increases
Solution Approach 1:
The base layer material (such as metal phthalocyanine or copper phthalocyanine) inherently forms a stable oxide layer through controlled oxidation during or after vapor deposition, eliminating the need for separate heat treatment processes while maintaining stable transistor performance
Solution Approach 2:
The base layer is designed to undergo controlled oxidation during the deposition process itself, pre-forming the necessary oxide characteristics before device assembly, thereby avoiding subsequent heat treatment steps
3Ease of manufacture
If conventional OFET structure is used, then ease of manufacture is maintained, but current output capability deteriorates due to low mobility
Solution Approach 1:
The transistor structure transitions from field-effect control to bipolar-like current control by introducing a thin base layer, fundamentally changing the operating parameters from voltage-controlled to current-controlled operation, thereby achieving high current output capability while maintaining vapor deposition fabrication
Solution Approach 2:
The device uses composite organic semiconductor materials with optimized charge transport properties in each layer, combining materials with complementary characteristics to achieve both high current capability and compatibility with vapor deposition manufacturing processes
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 device achieves stable large-current amplification and high on/off ratios, enabling efficient operation as a drive device for organic EL displays with improved contrast and reduced dark current, fabricated through a simple and cost-effective vapor deposition process.
Implementation Method 1
the first organic semiconductor layer has a diode structure of a p-type organic semiconductor layer and an n-type organic semiconductor layer
Implementation Method 2
incorporating a lithium fluoride layer for improved performance
Implementation Method 3
fabricated through a simple and cost-effective vapor deposition process
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A current-amplifying transistor device is provided, between an emitter electrode and a collector electrode, with two organic semiconductor layers and a sheet-shaped base electrode. One of the organic semiconductor layers is arranged between the emitter electrode and the base collector electrode, and has a diode structure of a p-type organic semiconductor layer and an n-type p-type organic semiconductor layer. A current-amplifying, light-emitting transistor device including the current-amplifying transistor device and an organic EL device portion formed in the current-amplifying transistor device is also disclosed.