Electrical properties of self-assembled InAs/InAlAs quantum dots on InP

Abstract

The characteristics of InAs self-assembled quantum dots (QDs) grown on InAlAs/InP (001) have been investigated by capacitance-voltage (C-V) measurements and deep-level transient spectroscopy (DLTS). The depth profile of the apparent electron concentration obtained by C-V measurements shows significant carrier accumulation around the position of the InAs QDs plane. In addition to the D 1 -D 5 traps, which are commonly detected in InAlAs layers grown on InP by molecular beam epitaxy (MBE), DLTS investigations show three InAs-related levels located at about 76, 202 and 246 meV below the InAlAs conduction band edge. The applied field is found to significantly enhance tunnel emission processes as seen in the broadening of the peaks with increasing reverse bias. The results suggest that defects in the material barrier can enhance electron tunnelling through barriers.

Tunnelling current in Schottky diodes containing InAs quantum dots

“…Assuming that the QD layer is introduced in the middle of the diode base and neglecting the band bending due to the potential of the ionised impurity in the diode base, one can estimate the energy gap between the electron levels in InAs nanoclusters at DE % e DV 2 % 175 meV. This value is in a reasonable agreement with the value of the energy gap between s and d levels of electrons determined by DLTS measurements [13].…”

“…Much work has been done on the transport and optical properties of InAs/GaAs and InGaAs/GaAs QDs structures [7][8][9][10]. Some studies have been devoted to the optical and electrical properties of the InAs/InAlAs nanostructures grown on InP [11][12][13][14][15]. However, the carrier transport mechanism in such QDs is less understood.…”