Stability of negative electron affinity Ga0.37Al0.63As photocathodes in an ultra

The stability of negative electron affinity Ga0.37Al0.63As photocathodes in an ultrahigh vacuum system has been investigated. The degraded photocurrents of the Cs/O activated Ga0.37Al0.63As photocathodes under illumination with different intensity are recorded in real time, and the quantum efficienc