Charging control of InP/GaInP quantum dots by heterostructure design

In English Semiconductor quantum dots are often charged due to accumulation from a doped host material. Using low-temperature photoluminescence, we have studied the charging of single self-assembled InP dots in structures designed to control the electron population in a weakly n-type environment. By using designed heterostructures to position the Fermi level of the structure, not requiring electric fields or currents, we show that the electron accumulation can be reduced from approximately 18 electrons in the dot to approximately 8 electrons. In particular, we show that the single quantum dot luminescence spectrum of the Fermi-level pinned structure perfectly matches the low-energy part of the highly charged reference spectrum, a phenomenon predicted by the model for multiple charging of quantum dots. (C) 2004 American Institute of Physics.