Electron escape from InAs quantum dots

We identify fundamental mechanisms of electron escape from self-organized I nAs quantum dots (QD's) in a vertical electric field by time-resolved capac itance spectroscopy. Direct tunneling and a thermally activated escape proc ess are observed. The QD electron ground and first-excited states are concl uded to be located similar to 190 and similar to 96 meV below the GaAs matr ix conduction band, respectively. Our experimental results and their interp retation are in good agreement with eight-band k.p calculations and demonst rate the importance of tunnel processes. [S0163-1829(99)01344-2].