The dynamics of tunneling into self-assembled InAs dots

Using frequency-dependent capacitance spectroscopy, the dynamics of tunneling into arrays of self-assembled InAs quantum dots is investigated with respect to sample geometry, Coulomb interaction, and magnetic field. An equivalent resistance-capacitance circuit is derived which allows us to determine the tunneling times for each state of the dots. The different tunneling times for different many-particle states are explained by a reduced tunneling barrier and Coulomb interaction. A magnetic field applied perpendicular to the tunneling direction results in a strong suppression of the charging signal, which is attributed to enhanced localization caused by the magnetic field. Calculations for three-dimensional to zero-dimensional magnetotunneling can account for the experimental data. (C) 1999 American Institute of Physics. [S0003-6951(99)01217-6].