From correlated SIMS and EPR studies on high resistive, vanadium doped
CdTe and ZnCdTe bulk crystals we have determined the total V concentr
ation [V] and the [V3+] and [V2+] concentration respectively. This all
ows us to estimate the effective trap concentration N-eff=[V2+][V3+]/[
V2+]+[V3+], which is one important parameter for photorefractive appli
cations. The values of N-eff obtained are in good agreement with those
previously deduced from photorefractive measurements.