Photograph of the PEEM chamber and its major components
Photoelectron emission microscope (PEEM)
This UHV-system houses a photoelectron emission microscope (PEEM) and a 4-grid low-energy electron diffraction (LEED) system which can also be used for Auger electron spectroscopy (AES). In addition, the chamber is equipped with tools for sample preparation (ion sputter gun, sample heating, electron beam evaporator for metals and sources for deposition of organic molecules) and a load-lock system for easy sample insertion. To increase the mechanical stability, the whole vacuum system rests on three air damping legs.
The PEEM is equipped with an integrated sample stage for ultimate stability and an imaging high-pass energy filter for imaging spectroscopy. A high-pressure mercury (Hg) UV-lamp with an emission maximum at 4.9 eV acts as a standard photon source. Additional light sources include a deuterium lamp (7.8 eV) and a He-I,II VUV source (21.2 eV, 40.8 eV). Optionally, secondary electron can also be imaged by the PEEM. For this purpose, an electron gun is mounted to the PEEM which can accelerate electrons up to 20 keV. The system allows the in-situ and real-time observation of the growth of organic molecules.
The already quite versatile set-up is supplemented by a UHV scanning probe microscopy system (combined atomic force (AFM) and scanning tunnelling microscopy (STM) system). Recently, an additional upgrade made it possible to cool the sample down to 50 K during STM/AFM investigation.
The combined STM/AFM - PEEM setup allows studying structures all the way from the atomic scale up to 150 µm.