Temperature-dependent energy gap variation in InAs/GaAs quantum dots

In this letter, we report a photoluminescence (PL) study of the temperature-dependent energy gap variation in InAs/GaAs quantum dots (QD). Energy gaps E(T) of different InAs/GaAs QD samples with various numbers of QD stacking layers were measured from the ground state PL emissions at various sample temperatures. For each of the QD samples, linear dependences between [E(T)-E-0](beta+T) and T (where E-0=0.42 eV and beta=-550 K) is obtained in low and high temperature regions. The transition temperatures between the two temperature regions are found to be related to the numbers of QD stacking layers. A linear relation between the number of the QDs and the phonon densities at the corresponding transition temperatures is obtained.