The degradation of quantum efficiency in negative electron affinity GaAs photocathodes under gas exposure

Patterned negative electron affinity photocathodes for maskless electron beam lithography

This work focuses on two issues crucial to achieving high throughput with a negative electron affinity semiconductor photocathode source. Monte Carlo simulations indicate that for a 50 kV system, as much as 8 mA of current may be delivered to the wafer to achieve a raw throughput of 20 8 in. wafers per hour with 0.1 mm minimum feature size ~assuming a resist sensitivity of 10 mC/cm!. In order t...

Thermal emittance and response time measurements of negative electron affinity photocathodes

The thermal emittance and temporal response of a photocathode set an upper limit on the maximum achievable electron beam brightness from a photoemission electron source, or photoinjector. We present measurements of these parameters over a broad range of laser wavelength for two different negative electron affinity NEA photocathodes. The thermal emittance of NEA GaAs and GaAsP has been measured ...

The Distribution of Oxide Species in the Cs/O Activation Layer on InP(100) Negative Electron Affinity Photocathodes

The atomic arrangement of Cs oxides in the activation layer of an InP photocathode is investigated using Angle Dependent Photoemission Spectroscopy (ADPES). Two distinct peaks in the O1s core level and in valence band spectra have led to the discovery of two molecular oxygen species incorporated in the thin activation layer: Cs peroxide (Cs2O2) and Cs superoxide (CsO2). The different angular de...

assessment of the efficiency of s.p.g.c refineries using network dea

data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...

Quantum- and transport electron mobility in the individual subbands of a two-dimensional electron gas in Si-S-doped GaAs