The role of space charge in GaAs-based particle detectors

The direct measurement of the captured charge using the Faraday cup method together with the analysis of current-voltage curves was used for the experimental proof of the existence of the space charge in biased GaAs detector structures. The role of this space charge was discussed using the generalized Ramo-Gunn's theorem which enabled the explanation of the data observed and, moreover, provides a useful criterion for the optimization of GaAs-based particle detectors. (author)