Equipment
Molecular Beam Epitaxy (MBE) Deposition Systems
Several UHV MBE systems equipped with e-beam evaporators and diffusion cells for depositing a variety of different materials from metals to molecules are available, including in situ characterization (i.e., Reflection High Energy Electron Diffraction (RHEED), Auger Electron Spectroscopy (AES), Scanning Tunneling Microscopy (STM)).
Magnetron Sputter-Deposition/MBE System
Home-build UHV magnetron sputtering system for depositing metals including rare earths (Gd, Tb) and dielectric thin films. An array of four magnetron sputtering sources using DC or RF power are operated in singly or in co-deposition mode (Ar sputter gas) to produce a wide variety of film compositions. The sputter chamber is connected to a MBE chamber equipped with an e-beam evaporator with two sources.
Pulsed Laser Deposition (PLD) Systems
Several PLD systems, where a laser beam is focused inside a vacuum chamber to strike a target of the material that is to be deposited, are available.
Organic molecular beam deposition (OMBD) and thermal metal evaporation
Several high vacuum chambers for organic molecular beam depostion (OMBD) are available at our chair. With these systems the deposition of organic thin films and organic blends with controlled mixing ration of two components is possible. Substrate heating to more than 100 °C and substrate cooling with liquid nitrogen is implemented in some of the chambers. For the fabrication of fully functional organic light emitting diodes (OLEDs), organic photovoltaics (OPVs) and organic field effect transistors (OFETs) thermal evaporation of metals for the contacts is required. At our institute some deposition chambers support the evaporation of metals and inorganic oxides in-situ to avoid a potential contamination of the organic layers.
Magnetic Force Microscope (MFM)
For magnetic characterization of nanoscale devices and structures, we use a custom-modified Digital Instruments (Dimension 3000) scanning probe microscope. The microscope is used for various types of scanning probe measurements allowing for external magnetic fields.
Magneto-optical polar Kerr magnetometer (MOKE)
Two home-built polar MOKE systems with external magnetic fields up to 2 T operating at RT allowing also angle dependent measurements are available. In addition a low temperature (2.5-300K) high field (9 T) polar MOKE system has been installed recently.
Tandem-Ion-Accelerator, HVEE 2MV (High Voltage Engineering Europe B.V.)
This setup is used for Rutherford Backscattering Spectrometry (RBS) using 4He ions. RBS is an analytical technique used to determine the composition and depth profiles of materials by measuring the backscattering of a beam of high energy ions impinging on a sample.
General Info: Maximum Voltage: 2 MV, Maximum Energy: 6.0 MeV (@ 4He++)
Injection Unit: RF He-Plasma Source, Charge Exchange Canal (CEC) using Li-vapour (~ 600°C), 90°-analyzing magnet
Accelerator Unit: SF6-insulated, Cockroft-Walton type HV power supply (capacitively coupled), HV terminal stripper system (N2), switching magnet
RBS analysis chamber: vacuum system, equipped for sample rotation (Phi-rotation/Theta-tilt), semiconductor detector.
Ion-Implantation-System, NV 3206 (Axcelis Technologies)
Ions of different materials are accelerated in an electrical field and impacted into a solid allowing modifying the physical properties of the solid.
General Info: Beam energy range: 20 to 200 keV (5 to 20keV optional) Implant angle: 0-15°, wafer size: 2“-4“, sample holders (up to 700°C or L-N2 cooled) Fabrication of stripes of different ion concentrations (movable x/y-shutters) The following elements have been successfully implanted: H, He, Li, B, C, N, O, Ne, Mg, Al, Si, P, S, Cl, Ar, Ca, Ti, V, Cr, Fe ,Ni, Cu, Zn, Ge, Se, As, Mo, Ru, Cd, Ag, Sn, Sb, Te, Xe, W, Pb, Ce, Eu, Gd, Er, Tm, Yb
Raman Spectroscopy (T64000)
The Raman effect, which is a light scattering phenomenon, is used to observe vibrational, rotational, and other low-frequency modes in a material system.
Secondary-Ion-Mass-Spectroscopy (SIMS)
SIMS is used to analyze the composition of solid surfaces by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions. From the mass/charge ratios of these secondary ions measured with a mass spectrometer the elemental or molecular composition of the surface (1 - 2 nm) is determined.
Superconductive Quantum Interference Device - Vibrating Sample Magnetometry (SQUID-VSM, LOT-QuantumDesign)
This magnetometer combines the high sensitivity (≤ 10-8 emu) of the SQUID with high speed of measurement of a conventional VSM.
Measurements can be performed with magnetic fields up to +- 7 Tesla in a temperature range from 2.5 K up to 1000 K.
Electro- and Photoluminescence Cryostates
Multiple liquid Nitrogen and Helium cryostates are available at our institute for measuring electro- and photoluminescence at temperature ranges between 350 to 4 K.
Glovebox
Many organic semiconductors are senstive to oxygen and water. This nitrogen glovebox allows for handling and storing our materials under inert gas atmosphere. Addtionally one depostion chamber for the evaporation of organic thin-films and metal contacts as well as many characterization techniques for our samples are directly accessible from this box in order to avoid a contamination from the ambient. For measurements at our other setups, the films are often encapsulated or transfered under nitrogen atmosphere.
Clean Room
In our clean room the substrates for the deposition are prepared. Additionally, wet processing via spin-coating is possible, there.
Scanning Magneto-Resistive Microscope (SMRM)
This home-built variable-temperature Scanning Magneto-Resistive Microscope (SMRM) is specifically designed for the study of magnetic thin films and arrays of nanostructures. This device uses a state-of-the-art magnetic recording head of a hard disc drive (HDD), which allows imaging as well as applying a local magnetic field pulse to individual magnetic structures.