One of the most difficult parts of solar cells are the generation of appropriate ohmic contacts. Using dopant segregation during nickel silicidation enables contacting emitters with almost arbitrary dopant concentration. In turn, this allows optimizing the emitter with respect to lowest recombination.
Two-dimensional material such as graphene and transition metal dichalcogenides are currently attracting an increasing attention. The reason is the ultrathin body thickness allowing for the realization of ultimately scaled FET without sacrificing electrostatic integrity. At the same time, they can be patterned with planar technology. In addition, heterostructures can easily be fabricated enabling an engineering of desired electronic properties.
To investigate carbon-based materials (mono- and bilayer graphene, carbon nanotubes) for advanced nanoscale field-effect transistors we fabricate buried triple- and multi-gate structures that enable the generation of a potential landscape in the direction of current transport. This is used to study e.g. band-to-band tunneling in these materials as well as alternative device concepts.
Multilayer structures consisting of Si/SiO2 are used in 3rd generation solar cells. Quantum confinement in the Si layers is used to tune the effective band gap to the desired size enabling an absorption of UV light while minimizing relaxation losses at the same time. The transmission electron micrograph clearly shows that continuous layers of Si and SiO2 with thicknesses down to 3nm can be grown.
Tunnel FETs (TFET) potentially offer a superior switching behavior compared to conventional transistors and have been intensively investigated in recent years. Optimization of the device performance is studied both experimentally as well as with simulations at our institute. The image shows the local density of states in a TFET enabling a high current injection into the channel.
The surface of solar cells is usually textured in order to suppress specular reflection of incident light yielding a significantly improved light to electricity conversion efficiency. The image shows a scanning electron micrograph of a typical texturing of a crystalline silicon solar cell.
March 18, 2016
Our institute has moved within the Walter-Schottky-Haus (WSH). From now on you find us on the second floor in building section C of the WSH. Please refer to the MEMBERS section on our homepage for the new room allocations and telephone numbers of our employees. Our postal address stays the same.
March 18, 2016
Filled with consternation we take leave of Professor Dr. phil. Heinrich Kurz who passed away on March 12th, 2016 at the age of 72.
Professor Kurz was an exceptional person with impressive achievements in science and in the organization of science.
After obtaining his doctoral degree in 1971 at the University of Vienna he worked for 10 years at the Philips Research Laboratories in Hamburg. He joined the group of Professor Nicolaas Bloembergen at Harvard University from 1981 to 1984 before he became Professor of Electrical Engineering at RWTH Aachen University in 1984. Three years later, in 1987 he received the “Alfried-Krupp-Förderpreis” Award in ultrafast optoelectronics for young university lecturers.
From 1990 to 2011 he headed the Institute of Semiconductor Electronics at RWTH Aachen University. His research activities span a broad spectrum including femtosecond spectroscopy, optoelectronics, terahertz applications and nanoelectronics.
He was a visionary leader, a great manager and organizer. He was also a person who could truly motivate and inspire people.
Our thoughts are with his family.
On behalf of all employees
Universitätsprofessor Dr. rer. nat. Joachim Knoch Dr. rer. nat. Karl Wolter
Head of Institute of Semiconductor Electronics Academic Director