Molecular-beam epitaxial growth and characteristics of highly uniform InAs∕GaAs quantum dot layers

We have investigated the molecular-beam epitaxial growth and structural and photoluminescence characteristics of self-organized InAs∕GaAs quantum dot bilayers, in which a first seed layer of stressor dots is followed by a GaAs barrier layer and a second layer of active dots. At room temperature, the peak emission wavelength is at ∼1.4μm. By optimizing the growth parameters for both dot layers and the GaAs barrier layer, we have measured photoluminescence linewidths of 10.6 and 17.5meV at 20 and 300K, respectively. The measurement and analysis of temperature-dependent photoluminescence data indicate that there is no observable carrier redistribution amongst the dots with an increase of temperature and there is a high degree of size uniformity. The photoluminescence linewidth of 17.5meV at 300K is almost identical to that measured in the emission from a single dot, indicating that the linewidth is determined by homogeneous broadening.