Quantum dot nano-cavity emission tuned by a circular photonic crystal lattice

In this work the analysis, fabrication and optical characterization of a circular two-dimensional photonic crystal (2D-CPC) nano-resonator based on a air/GaAs/air slab waveguide are presented. Four InAs/InGaAs quantum dots (QDs) stacked layers emitting around 1300 nm were embedded in a GaAs waveguide layer grown on an Al_0.7Ga_0.3As sacrificial layer. The nano-resonator was realized by drilling 2D-PC air holes arranged in a circular lattice configuration through electron beam lithography (EBL), inductively coupled plasma (ICP) etching and wet selective etching of the Al_0.7Ga_0.3As sacrificial layer in order to release the membrane. The spectral response of the active circular nano-cavity has been simulated by using a three dimensional finite-difference time-domain method (3D-FDTD) as a function of both the inner and outer holes radius/period ratios of the photonic crystal structure. Good agreement between the calculated resonance and the experimental results, recorded from the nano-cavity by a μPL setup, has been achieved.