Evolution of photoemission properties on Cs/GaAs and GaAs(Cs,O) surfaces under thermal cycling

The photoemission properties on Cs/GaAs and GaAs(Cs,O) surfaces prepared at room temperature were studied under thermal cycling. The evolution of electron affinity and escape probability to vacuum was measured using photoemission quantum yield spectroscopy for the surfaces with various Cs-O overlayer compositions. It was found that an increase in the oxygen exposure led to the improvement in the thermal stability of electron affinity. (paper)