The novel surface science instrument: Double reflection electron emission microscope

A universal UHV instrument, the double reflection electron emission microscope (DREEM), for surface imaging, diffraction, and local (1 μm resolution) measurements is presented. DREEM consists of three fully electrostatic lens systems: electron gun column, immersion objective lens, and imaging column. The novel illumination system incorporates an electron microreflector in the back focal plane of the objective, where the perpendicular optical axes of the electron gun and imaging column cross. The electron microreflector consists of the tip of a (001)-oriented single-crystalline W wire with a face of area 200 μm2. The primary electrons of energy from 1 to 6 keV elastically reflect from the W tip surface and are decelerated between the objective and grounded sample to the desired impact energy from 0 eV to 5 keV. Numerous contrast mechanisms are expected for image formation with DREEM including topographic, magnetic, chemical (Auger, core level), phase shift, and work function. The instrument is capable of operating in low energy electron diffraction, mirror electron microscopy, low energy electron emission microscope, and photoelectron emission microscope modes. The first results obtained with the DREEM are presented.