We present a study of carrier redistribution in InxGa1-xAs/GaAs self-assembled quantum dots (QDs) by comparing electroluminescence (EL) and photocurrent (PC) spectra. We show the existence of a red-shift of the dot emission in EL relative to the dot absorption in PC, referred to as the Stokes shift (SS). The existence of the SS is explained in terms of a thermal redistribution of carriers between dots. According to the thermalization model, the SS increases with the linewidth of the QD absorption spectrum. We show that for a large variety of quantum dots, differing in the material system and/or the growth technique, the SS has a universal dependence on the QD absorption linewidth.
Universality of the stokes shift for a disordered ensemble of quantum dots / A., Patane; A., Levin; Polimeni, Antonio; L., Eaves; P. C., Main; M., Henini; G., Hill. - In: PHYSICA STATUS SOLIDI B-BASIC RESEARCH. - ISSN 0370-1972. - STAMPA. - 224:1(2001), pp. 41-45. [10.1002/1521-3951(200103)224:1<41::aid-pssb41>3.0.co;2-s]
Universality of the stokes shift for a disordered ensemble of quantum dots
POLIMENI, Antonio;
2001
Abstract
We present a study of carrier redistribution in InxGa1-xAs/GaAs self-assembled quantum dots (QDs) by comparing electroluminescence (EL) and photocurrent (PC) spectra. We show the existence of a red-shift of the dot emission in EL relative to the dot absorption in PC, referred to as the Stokes shift (SS). The existence of the SS is explained in terms of a thermal redistribution of carriers between dots. According to the thermalization model, the SS increases with the linewidth of the QD absorption spectrum. We show that for a large variety of quantum dots, differing in the material system and/or the growth technique, the SS has a universal dependence on the QD absorption linewidth.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
