Optimization of Record-High-Frequency Vertical Organic Transistors

_{February 2020}

© IAP

Organic transistors promise very interesting applications like bendable displays or low‑cost electronics that can be processed in roll-to-roll coating machines. For many applications the maximum frequency that can be achieved in a transistor is a main figure of merit. This frequency, called the transition frequency, is largely dependent on the maximum current density in the device. Since every transistor has a certain built-in capacitance, a large current density is needed to quickly charge and discharge the device in a high-frequency application.

The world’s fastest organic transistor is the Organic Permeable Base Transistor, which is a vertically assembled device that cleverly uses thin-film technology to create ultra-small devices with very little processing effort. The small dimensions allow for large current densities and consequently large frequencies of up to 40 MHz. We have established a profound understanding of the nano-processes involved in the formation of this device, based on which we want to further improve the device performance and set the next benchmarks for very fast organic transistors.

With this master topic, we want to investigate promising approaches for optimizations of our devices:

• Controlled interface doping for reduced leakage current

• Further reduction of device thickness for increased on-current

• Optimization of electrode conductivity

• Design improvements for thermal power management

The master student will be integrated into our research group at IAPP, where more than 120 international researches collaborate in a friendly and creative atmosphere. There will be a structured supervision by Dr. Felix Dollinger, who is an experienced researcher in the field. The student will be introduced to our facilities and tools and help will be given in order to facilitate independent work on the master topic.

The student will take an active part in research-group meetings, close collaborations and mutual support within the group.

Since a good understanding of the device function and of our manufacturing processes is needed, this topic is best suited student who want to be involved for more than a few weeks: Physics master students or for OME students, who combine their project work and the master thesis on this topic.

Recent publications on the topic:

• Electrically stable organic permeable base transistors for display applications, Dollinger et al., Advanced Electronic Materials, 2019, DOI: 10.1002/aelm.201900576

• Vertical organic thin-film transistors with an anodized permeable base for very low leakage current, Dollinger et al., Advanced Materials, 2019, DOI: 10.1002/adma.201900917

• Scaling of high-performance organic permeable base transistors, Al-Shadeedi et al., Advanced Electronic Materials, DOI: 10.1002/aelm.201800728

contact person:
Dr. Felix Dollinger
felix.dollinger@tu-dresden.de