Study of the Structural and Luminescence Properties of InAs/GaAs Heterostructures with Bi-Doped Potential Barriers

Resumo

The influence of Bi in GaAs barrier layers on the structural and optical properties of InAs/GaAs quantum-dot heterostructures is studied. By atomic-force microscopy and Raman spectroscopy, it is established that the introduction of Bi into GaAs to a content of up to 5 at % results in a decrease in the density of InAs quantum dots from 1.58 × 10¹⁰ to 0.93 × 10¹⁰ cm^–2. The effect is defined by a decrease in the mismatch between the crystal-lattice parameters at the InAs/GaAsBi heterointerface. In this case, an increase in the height of InAs quantum dots is detected. This increase is apparently due to intensification of the surface diffusion of In during growth at the GaAsBi surface. Analysis of the luminescence properties shows that the doping of GaAs potential barriers with Bi is accompanied by a red shift of the emission peak related to InAs quantum dots and by a decrease in the width of this peak.