Infrared optical versus transport spectroscopy for few-electron spherical quantum dots

The problem of detection of few-electron states has been studied for spheri cal quantum dots both with and without a donor centre. The confinement pote ntial is assumed to be a three-dimensional spherical potential well of fini te depth and range. The variational method has been applied to calculate bo und states of one-, two-, and three-electron systems confined in donor-dope d and undoped quantum dots. We have shown that the chemical potentials of t he systems considered are significantly different, in contrast to the intra band optical dipole transition energies, which are almost indistinguishable . Therefore, the transport and capacitance spectroscopy techniques should y ield clear evidence for the presence of a donor impurity in the quantum dot .