Dynamic response of 1.3-μm-wavelength InGaAs/GaAs quantum dots

• Published in: Applied physics letters Vol. 76; no. 10; pp. 1222 - 1224
• Main Authors: Zhang, L., Boggess, Thomas F., Deppe, D. G., Huffaker, D. L., Shchekin, O. B., Cao, C.
• Format: Journal Article
• Language: English
• Published: 06-03-2000
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.125991

The temperature-dependent dynamic response of 1.3-μm-InGaAs/GaAs quantum dots is investigated using time-resolved photoluminescence upconversion with subpicosecond temporal resolution for excitation in either the GaAs bulk region surrounding the dots or within the wetting layer. Relaxation to the quantum-dot ground state occurs on a time scale as short as 1 ps, while radiative lifetimes as short as 400 ps are measured. The influence of nonradiative recombination is observed only for temperatures above 250 K. At temperatures below 77 K, an increase in the relaxation time and lifetime is observed when carriers are injected into the bulk GaAs region versus excitation into the wetting layer, which suggests that diffusion in the bulk GaAs region influences both the relaxation rate and the recombination rate.