InP/InGaAs nanofabrication and optical characterization

We have developed InGaAs/InP quantum wires and quantum dots with lateral extensions below 20 nm by high resolution electron beam lithography and wet chemical etching. In contrast to dry etched structures the wet etched wires and dots are found to be virtually free of significant optically inactive (“dead”) sidewall layers. Time resolved measurements yield rather long lifetimes of about 500 ps for 20 nm wide deep etched wires. The luminescence of the wires and dots shows a strong shift to higher energy as well as features due to transitions between up to four lateral subbands when the characteristic widths is reduced below 50 nm. Due to the absence of optically inactive sidewall layers the size variation of the emission energy can be modeled quantitatively based on the measured widths of the nanostructures