Planar CdTe detectors with different performances for gamma radiation detection have been investigated. The detector internal electric field was analyzed by means of time-of-flight experiments. The correlation of the results with the current-voltage characteristics of the samples, their risetime distribution for different gamma irradiation and, eventually, the shape of detected gamma spectra led us to a detector model based on the theory of space charge limited current.
Using this model, we try to explain operation and failure of trapping loss correction methods for the different detector groups.