1. Quantum Dot NanoCavity Emission Tuned by a Circular Photonic Crystal Lattice CNR-INFM Lecce (Italy) National Nanotechnology Lab Web: http://www.nnl.it/ vito.errico@unile.it International School of Nanophotonics September 14-22, 2007 - Maratea (Italy) Vito Errico

2. Outline State of the art on nanocavities and whispering gallery devices Standard photonic crystals vs Circular photonic crystals (CPC) Simulations of 2D CPC cavity Fabrication of membrane QD cavity Optical characterization of 2D-CPC Nano-Resonator

3. Experimental QDs epitaxially growth by molecular beam epitaxy (MBE) Ground state QD emission around 1288nm Dot density: 3.2·10 10 cm -2

4. Experimental Electronic exposure and resist development o Acceleration voltage: 20 keV o Aperture size: 7.5 o Dose: 38  C/cm 2 o Circular mode and Proximity Error Correction (PEC) were used Dry-etching by ICP plasma etching o Gas involved: SiCl 4 /He (16sccm/4sccm) o Platen power: 60W o Pressure: 2mtorr Sacrificial layer removal by wet-etching o HF:H 2 O (1:10) at room temperature

5. Fabrication Results SEM image of the nano-cavity after processing procedure Brighter area corresponds to Al 0.7 Ga 0.3 As removal The four rectangles on each side of the nano-cavity structure assist wet-etching process [1] V. Errico et al. / Microelectronic Engineering 84 (2007) 1570–1573

6. Fabrication Results SEM image of totally suspended nano-cavity after processing procedure

7. Optical Characterization Results Cavity parameter: a:350nm r i /a = 0.47 r o /a = 0.67 Peak: Center: 1282nm FWHM: 0.62nm Quality factor: Q≈2000 [2] V. Errico, et al., High-Q factor single mode circular photonic crystal nano- resonator, Superlattices and Microstructures (2007), doi:10.1016/j.spmi.2007.06.013

8. Conclusion Circular nano-cavities behaviour has been simulated to match cavity resonance and QDs emission. CPC device based on air/GaAs/air membrane has been realized. QDs Nano-Cavity emission has been tuned by a circular photonic crystal lattice This technology is being applied to: Whispering gallery modes device CPC technology based Electrical injected CPC laser

9. Thanks for your attention