Capacitance-voltage profiling of Au/n-GaAs Schottky barrier structures containing a layer of self-organized InAs quantum dots

Capacitance-voltage measurements are used to obtain profiles of the free carrier distribution in Schottky barriers grown on uniformly doped n-GaAs hosts containing layers of self-organized InAs quantum dots. It is found that electrons accumulate at a depth of 0.54 mu m, which corresponds to the depth of the quantum-dot layer. As the temperature drops below 90 K, a second peak appears in the concentration profile at 0.61 mu m, which becomes dominant as the temperature continues to decrease. It is shown that the appearance of the second peak in the concentration profile is not due to electron density redistribution over the structure, but rather is observed when the rate of thermal emission of electrons from the quantum dots is slower than the angular frequency of the capacitance measurement signal. (C) 1998 American Institute of Physics. [S1063-7826(98)01810-9].