Cathodoluminescence of surface-charged Ce:YAG crystals was carried out
. it was found that the familiar YAG defect emission band at 300 nm ha
d a stronger dependence on the incident electron beam energy and accum
ulated surface charge than the cerium emission band at 550 nm. Lumines
cent relaxations, observed upon charging and discharging, appear to be
due to charge migrations within the active region of crystal bulk. Th
e experimental results are consistent with the association of the defe
ct luminescent center with electrons trapped at oxygen vacancies.