Sample positioner and deflection energy analyzer for measurements of photofield emission

摘要

A sample positioner and an electron energy analyzer for studies of photofield emission have been designed and constructed. The sample positioner allows photofield emission from every facet of a field emitter to be measured under illumination at arbitrary angles of light incidence and polarization. The electrons emitted from a selected facet are decelerated to a kinetic energyE0by a series of cylindrical lenses and introduced into either one of two energy analyzers. The deflection energy analyzer, formed from two identical 127deg; cylindrical analyzers, is used when highhyphen;energy resolution is required. The full width at halfhyphen;maximum height of the resolution function of this analyzer is proportional toE0down to a minimum kinetic energy which is less than 0.5 eV, and is given by Dgr;EFWHM=(0.0390plusmn;0.0006)E0. The throughput depends onE0due to a combination of resolution and aperturing effects, and varies asE3/20. The signalhyphen;tohyphen;noise ratio of the analyzer is limited to 2times;104by inelastic scattering of electrons. The retardation energy analyzer is used for aligning the system and for measuring the energyhyphen;integrated current.