Shape Changes in Patterned Planar InAs as a Function of Thickness and Temperature

摘要

Quantum dots have the potential to produce devices with enhanced properties. However, many quantum dot devices require the quantum dots to have a precise size and a precise location for optimum operation. So far approaches such as directed assembly and self assembly have failed due to the random effects resulting during nucleation of the quantum dots. InAs grown under metal rich conditions can remain planar as opposed to forming the self assembled quantum dot morphology. Recently we have demonstrated that planar InAs when patterned via tip-based scribing and then annealed under an As pressure typical for self-assembled quantum dot growth reorganizes and assumes a 3D morphology. We have been studying this process as a potential method to precisely locate quantum dots with definable sizes. In this work we report change in the morphology for different thickness of planar InAs for various pattern dimensions and annealing temperatures. We have analyzed the composition of the films after annealing to determine the effect induced in the films from patterning resulting from scribing. Using this approach, arrays of 3D InAs mounds have been formed with mounds having base dimensions of 800, 500, and 350A. These results demonstrate that the smaller patterns are less stable and coarsening becomes more dominant.