Title: Photoluminescence of ultra small InAs/GaAs quantum dots
Authors: Lin, YG
Wu, CH
Tyan, SL
Lin, SD
Lee, CP
Department of Electronics Engineering and Institute of Electronics
Keywords: excitation-dependent;PL;InAs;QD;redshift;tunneling;scattering
Issue Date: 10-Aug-2005
Abstract: The InAs/GaAs quantum dots (QDs) with a baselength of less than 10 nm are studied by the excitation-, temperature-dependent and magneto-photoluminescence (PL). The baselengths of the QDs, calculated by the PL ground state transition energy and estimated by magneto-PL spectra, axe in agreement with the result of atomic force microscopy measurements. By means of the excitation-dependent PL, we demonstrate that only the ground electron and hole states exist when the baselength of the QDs is smaller than about 7.3 nm, whereas the larger dots with a baselength of about 8.7 nm will give rise to one excited hole state. The measured energy separation between the ground and the excited hole states is in good agreement with the theoretical calculation. The transition energy in temperature-dependent PL spectra shows a rapid redshift as the temperature is higher than the critical temperature. The redshift rate is about 2.8 and 2.5 times larger than the values calculated by Varshni's law for small and large dots respectively. The higher redshift rate can be explained by the stronger tunneling effect. In addition, the PL linewidths show a V-shape dependence with the temperature. This behavior could be well described as a tunneling and electron-phonon scattering effect.
URI: http://dx.doi.org/10.1142/S021798490500892X
ISSN: 0217-9849
DOI: 10.1142/S021798490500892X
Volume: 19
Issue: 18
Begin Page: 907
End Page: 917
Appears in Collections:Articles