Quantum-mechanical device concepts including ultra-thin functional ALD-films for terahertz applications

• Applicants: Professor Dr. Johann-Wolfgang Bartha; Professor Dr.-Ing. Christian Wenger
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2013 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 226970965

The terahertz frequency range currently constitutes one of the central strategic research fields for numerous technical applications. In contrast to previous approaches, the here-proposed concept study favors a frequency generation based on quantum-mechanical devices. The main aim of thisproject is to obtain a fundamental understanding of the relevant factors in the production of such quantum-mechanical devices. As the films included therein span only a few atomic layers, the functional material properties of the individual layers and the behavior of interfaces between adjacentlayers will be considered in addition to the characteristics of a device demonstrator in its entirety. So, this project does not focus on the mere production of a complete transistor and its electrical evaluation. Instead, this research service will concentrate on three basic aspects that are crucial forthe functionality of quantum-mechanical devices in terahertz applications: First, the initial growth of ultra-thin functional layers will be investigated at exactly the place (in situ) and in real-time of the atomic layer deposition (ALD) processes. For this purpose, a vacuum cluster tool combines variousdirect and indirect surface analysis methods (photoelectron spectroscopy, scanning probe microscopy, ellipsometry, mass spectrometry) in a worldwide unique manner and thus provides an extraordinarily detailed insight into the ALD growth actions down to the sub-atomic level. Second, ultrathin graphite layers will be synthesized and their vertical transparency with respect to hot electrons will be characterized using a diode-like device which represents the core of a tunneling hot electron transistor. Third, the interaction of ultra-thin ALD films with the ultrathin graphite layer will be studied on the basis of a device-based process route implemented for the first time.

• DFG Programme: Research Grants
• Co-Investigators: Dr.-Ing. Matthias Albert; Dr. Grzegorz Lupina, Ph.D.