Effects of stress on formation and properties of semiconductor nanostructures

Quantum wires and quantum dots are semiconductor structures with two or more physical dimensions on the order of 10 nm or smaller. These structures have applications in nanoelectronics, optoelectronics, information technology, and biotechnology because of the quantum mechanical confinement provided by the small spatial extent of the structures. At these very small scales, the continuum approximation breaks down and it becomes necessary to model the materials at the atomistic level; and the electronic and mechanical properties become strongly coupled physically. Experimental evidence shows that mechanical stress has important effects on semiconductor nanostructure systems in terms of both fabrication and device applications. This chapter provides an overview of issues in modeling of stress effects on formation and properties of semiconductor nanostructures. It discusses applications of these structures and the modeling methods available for studying quantum dots and wires. The chapter describes the following problems of stress effects on semiconductor nanostructure formation: stress-driven self-assembly of quantum dots, the sputter erosion surface instability, and the stress-affected phase separation in semiconductor alloys. It discusses the three areas in which stress affects semiconductor nanostructure device properties: (1) the stress effect on parallel transport in semiconductor films, (2) the effects of stress on electronic and optical properties of quantum dots and quantum wires, and (3) the multiscale modeling of coupled mechanical/electronic properties in semiconductor nanostructures. The chapter briefly discusses the prospects and challenges for future modeling of stress effects in semiconductor nanostructures.