Lateral conductivity effects have been investigated in self-organised InAs
quantum dot (QD) structures grown in a GaAs matrix with different cap
layers. Current-voltage (I-V), capacitance-voltage (C-V), DLTS, capacitance
and conductance frequency dependence, fast defect transient (FDT),
and electron beam induced conductivity (EBIC) measurements were applied.
The conductivity in the QD plane decays within a distance of 10 microns.
The capacitance transients are dominated by the local QD-plane transversal
conductivity and by the free carrier transport in the cap layer.
The nonequilibrium free carrier created by electron beam excitation
develop a potential barrier at macroscopic distances from the electrical