Electric field modulation of exciton recombination in InAs/GaAs quantum dots emitting at $1.3μm$

Changing the electric field applied to InAs quantum dots embedded in a $p-i-n$ diode was found to modulate the radiative recombination rate of excitons in the dots. The quantum dots were capped with a strain-reducing layer to realize $1.3μm$ photoemission and a large dipole moment to the exciton states. The exciton states in a quantum dot were investigated by measuring the quantum-confined Stark shift for various applied electric fields and were compared with the theoretical electron and hole wave functions calculated using an eight-band $k⋅p$ model. When the absolute value of the applied electric field was reduced from $−82.4kV/cm$ to 0, the radiative recombination rate increased from 0.88 to $1.11ns−1$⁠. Comparison of the experimental rate with the calculated one revealed that the increase in the radiative recombination rate was due to a decrease in the overlap integral between the electrons and holes. These optical characteristics of InAs quantum dots are especially important for developing optical devices that use single photons and single charges because the contribution of nonradiative processes is smaller than that of the radiative process.