Effects of a thin nitrogen-doped layer on terahertz dynamics in GaAs containing InAs quantum dots

Abstract

The transient terahertz signal generated by electron diffusion that was excited by an ultrashort pulse was observed to vary with the potential structure around the surface. The formation of InAs quantum dots caused the strain field and the nitrogen atoms to further modify the potential structure around the quantum dots. The terahertz signal that was observed for various pump energies exhibited an interesting phase change. Further, the change in terahertz dynamics originated from the formation of a dilute nitrogen layer around the quantum dots. Furthermore, this change depends on the position of the nitrogen-doped layer. The results of this study provide important information for controlling the optical properties of quantum dots.