Engineering strain-induced self-rolling semiconductor tubes through geometry and patterning

Abstract

This thesis investigates the effect of the geometry of the strained bilayer mesa on the physical shape of semiconductor nanotubes, which is essential for precise positioning and uniform large area assembly. Experimental and simulation results of the rolling behavior of tubes are discussed for various geometries. The study attempts to understand the energy minimization process of strained heterofilms at the nanoscale level and to successfully interpret these phenomena for design and control of semiconductor nanotubes. Generally, III-V compound semiconductor tubes tend to roll up along the length of the mesa due to the lowest energy associated with the state in contrast to short side or mixed rolling behavior. However, the configuration of tubes can be modified by engineering the mesa geometry through additional patterning. Possible applications of new structures and devices obtained through semiconductor nanotubes are considered.