Ordering of Wires and Self-Assembled Dots on Vicinal Si and GaAs (110) Cleavage Planes

Abstract

The ability to precisely control the growth of semiconductor quantum dots and quantum wires is a topic that has recently attracted much interest worldwide. Such nanostructures can be fabricated by e. g., self-assembly, induced by elastic strain relaxation in lattice-mismatched systems like GaAs/InAs or Si/Ge. In addition to the recent progress made in growing quantum dots of well-defined size and shape the controlled positioning of self-assembled dot and wire systems is one of the major challenges of today’s heteroepitaxy. The main methods for preparing state of the art quantum dots are molecular beam epitaxy (MBE) (e. g., [1]) or epitaxy by chemical vapor deposition (CVD) (e. g., [2]). Different methods have also been applied to achieve a spatial ordering or well-defined positioning of such self-assembled nanostructures. One possible approach is the exploitation of modified growth kinetics which occurs e. g., on high index vicinal surfaces with regularly ordered atomic steps. These growth techniques have been used, for example, to grow In(Ga)As quantum dots and wires on (311)A or B GaAs (e. g., [3, 4]), on miscut (100)-oriented GaAs [5] or at crystal defects [6]. Other methods are based on modifying the surface morphology and subsequent growth or regrowth of the quantum dot structures (e. g., [7]). One of the most common approaches is the use of lithographically patterned substrates as templates in order to force controlled dot nucleation (e. g., [8–10]).