InAs Quantum Dots Grown on Selective Areas with a Metal Mask for Photonic-Crystal-Based Ultra-Small and Ultra-Fast All Optical Devices

A metal-mask (MM) method for selective-area-growth (SAG) of self-assembled InAs quantum dots (QDs) on a GaAs substrate was developed for applications of ultra-small and ultra-fast all optical devices based on a combination of QD and photonic crystal waveguides (PC-WGs). Successful SAG of QDs with high density and high optical quality comparable to conventional InAs-QDs grown without the MM was confirmed by atomic force microscopy and photoluminescence (PL) measurements. The QD density was 4times10¹⁰ cm^-2 and FWHM of the PL emission was around 30 meV at room temperature. By insertion of a strain-reducing layer on the QD, the PL peak wavelength was controlled from 1240 nm to 1320 nm. The MM method is promising for realizing the PC-based all optical devices, which require SAG of QDs and a QD ensemble with a different absorption-peak wavelength in a different area.