Finite element analysis of strain effects on electronic and transport properties in quantum dots and wires

Lattice mismatch in epitaxial layered heterostructures with small characteristic lengths induces large, spatially nonuniform strains. The components of the strain tensor have been shown experimentally to affect the electronic properties of semiconductor structures. Here, a technique is presented for calculating the influence of strain on electronic properties. First, the linear elastic strain in a quantum dot or wire is determined by a finite element calculation. A strain-induced potential field that shifts and couples the valence subbands in the structure is then determined from deformation potential theory. The time-independent Schrodinger equation, including the nonuniform strain-induced potential and a potential due to the heterostructure layers, is then solved, also by means of the finite element method. The solution consists of the wave functions and energies of states confined to the active region of the structure; these are the features which govern the electronic and transport properties of devic...