Resonant tunneling through energy states of InAs quantum dots in GaAs metal-semiconductor diode structures

Direct electronic transport properties in a GaAs metal-semiconductor diode structure containing InAs self-assembled quantum dots are reported. Current peaks and negative differential resistance due to resonant tunneling throu gh the zero-dimensional states of the InAs dots are clearly observed under reverse biases. The second derivative of the current versus voltage shows m ore structures at larger voltages, which are attributed to the resonant tun neling through the excited states of the quantum dots. From the peak positi ons in the second derivative, the energy separations between the states of the quantum dots are roughly estimated according to a simple calculation ba sed on our experimental data. (C) 2001 Elsevier Science B.V. All rights res erved.