Graphene has recently attracted a great deal of interest due
to its excellent electronic transport properties and its
geoemtrical smallness that allows realizing ultimately scaled
field-effect transistors without loosing electrostatic integrity.
We fabricate buried triple- and multi-gate structures that enable
studying e.g. graphene nanoribbons, bilayer graphene
as well as alternative 2D systems in a field-effect transistor configuration.
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) with a superior switching behavior have been intensively investigated in recent years since they allow realizing energy efficient logic circuits. 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 tunneling current to flow from source to 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 14, 2014
Tunnel field-effect transistors (TFETs) are very promising because of their unique circuit properties and low power consumption. Hence we want to use TFETs for mobile sensor applications combined with a cantilever based design. We offer a bachelor/ master thesis for students in the field of electrical engineering, physics or material science with the topic simulation of TFETs for sensor applications. Core task is to implement a TFET model in a finite element simulation program and improve the design parameters based on possible applications.
May 23, 2012
In this work we report for the first time on successful direct contacting of high sheet resistance emitter at 100 Ohm/sq by emitter profile manipulation. The formation of lightly doped emitter via POCl3 diffusion was investigated and optimized by the variation of temperature, time and gas … Read More...