| dc.description |
The effects of bias voltage and cladding layer thickness on the surface photovoltage in the semiconductor/electrolyte system (PSE) of InAs/GaAs quantum dot (QD) structures grown by atmospheric-pressure metal organic vapour phase epitaxy have been investigated. It was shown that the effect of compensation of the normal component of the photovoltage by the lateral component in the structures with an asymmetric point ohmic contact may help to reveal details of the energy spectrum of the QDs. Using this effect, it was shown that emission of electrons and holes from the QDs to the barrier at strong electric field occurs directly from the excited levels, without relaxation to the ground state. The observed broadening of the optical transition lines in QDs in a strong electric field was related to the lifetime of the carriers in the excited levels in QDs, according to the uncertainty relation. The lifetime of the carriers in QDs was limited by the carrier emission rate from QDs to the matrix through a triangle barrier at strong electric field. The possibility of in situ investigation of the processes of formation and passivation of the surface traps resulting from electrochemical reactions in the electrolytic cell by PSE spectroscopy has been demonstrated. |
