Electroluminescence of self-assembled InAs quantum dots in p-i-n diodes

Carrier injection and subsequent radiative recombination in InAs/GaAs self- assembled quantum dots (SADs) is investigated by means of a double-hetero ( DH) p-i-n structure, where a SAD layer is embedded at the center of the nar row intrinsic GaAs region. Low temperature electroluminescence shows clearl y the filling of electronic states of the dots with increasing voltage. Rel ating the experimental data to the calculated band structure, the onset of excited SAD-level luminescence is closely related to the occupation of the excited hole levels. whereas the electron levels seem to be filled to a hig her degree throughout the investigated voltage regime.