Control of Dip Shape in Photonic Nanostructures by Maskless Wet-Etching Process and Its Impact on Optical Properties

摘要

We demonstrate that maskless wet etching of self-assembled Ge quantum dot (QD) multilayers permits us to realize large-area photonic nanostructures, and their dip shape can be tuned by controlling structural parameters in the Ge QD multilayers. It is found that the reduction of Si spacer thickness brings about an increase in the dip depth and causes a reduction of reflectance at all the wavelengths. Furthermore, the presence of photonic nanostructures was shown to lead to the enhancement of photoluminescence intensity from Ge QDs. These results demonstrate that photonic nanostructures formed by this technique can enhance optical absorption in Ge QD multilayers.