TY - JOUR
T1 - An investigation of quantum states in ultra-small inas/gaas quantum dots by means of photoluminescence
AU - Wu, C. H.
AU - Lin, Y. G.
AU - Tyan, S. L.
AU - Lin, S. D.
AU - Lee, C. P.
PY - 2005/8
Y1 - 2005/8
N2 - The quantum states of InAs/GaAs quantum dots (QDs) with a base length of less than 10 nm are studied by means of excitation and temperature dependent photoluminescence (PL). The base length of the QDs, calculated by the PL ground state transition energy, is in agreement with the atomic force microscopy measurements. By means of the excitation-dependent PL, we demonstrate that only the ground electron and hole states exist when the base length of the QDs is smaller than about 7.3 nm, whereas larger dots, with a base length of about 8.7 nm, 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 the temperature-dependent PL spectra shows a rapid redshift as the temperature is raised 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-shaped dependence on the temperature. This behavior can be described as a tunneling and electron-phonon scattering effect.
AB - The quantum states of InAs/GaAs quantum dots (QDs) with a base length of less than 10 nm are studied by means of excitation and temperature dependent photoluminescence (PL). The base length of the QDs, calculated by the PL ground state transition energy, is in agreement with the atomic force microscopy measurements. By means of the excitation-dependent PL, we demonstrate that only the ground electron and hole states exist when the base length of the QDs is smaller than about 7.3 nm, whereas larger dots, with a base length of about 8.7 nm, 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 the temperature-dependent PL spectra shows a rapid redshift as the temperature is raised 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-shaped dependence on the temperature. This behavior can be described as a tunneling and electron-phonon scattering effect.
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M3 - Article
AN - SCOPUS:30444453105
SN - 0577-9073
VL - 43
SP - 847
EP - 855
JO - Chinese Journal of Physics
JF - Chinese Journal of Physics
IS - 4
ER -