Auger-photoelectron coincidence spectroscopy

点击翻译按钮获取中文摘要

Photoelectron spectroscopy and Auger electron spectroscopy are widely used for investigations of surfaces. Fundamental studies of Auger processes, however, are still developing. Interesting phenomena such as site-specific Auger, Auger subsequent to a shake-up photoemission and cascade Auger are not fully elucidated yet. By assembling a miniature cylindrical mirror electron energy analyzer (CMA) with a diameter of 26 mm in a coaxially symmetric mirror analyzer coaxially and confocally we have developed an apparatus for Auger-photoelectron coincidence spectroscopy (APECS). The CMA consists of a shield for electric field, inner and outer cylinders, a pinhole, and an electron multiplier. The performance was tested by measuring Si LVV Auger - Si 2p photoelectron coincidence spectra of a Si(111) surface. Features of the APECS apparatus are as follow. 1) Coincidence signal detection efficiency is improved by one order of magnitude from previous ones because of the large solid angle of the coaxially symmetric mirror analyzer and the CMA. 2) Positioning is quite easy, because the coaxially symmetric mirror analyzer and the CMA are assembled confocally on a rod with a mechanism for xyz positioning and tilt adjustment. 3) It can be installed to a multi-purpose ultrahigh vacuum chamber because it is constructed on a 203-mm-outer-diameter conflat flange with a 50-mm-retractable mechanism. 4) The production cost is low because the structure is simple and the number of the parts is relatively few.