We present a temperature- and bias-dependent photocurrent study of the exci
tonic interband transitions of InAs self-assembled quantum dots (QD's). It
was found that the carrier escape process from QD's is dominated by hole es
cape processes. The main path for this hole escape process was found to be
thermal-assisted hole tunneling, from the dot level to the GaAs barrier via
the wetting layer as an intermediate state. Energy-dependent carrier tunne
ling from the QD's to the barrier was observed at low temperatures. Energy
shifts due to the size-selective tunneling effect and the quantum-confined
Stark effect are discussed and compared with the carrier redistribution eff
ect in photoluminescence measurements.