Electronic properties of InAs/GaAs nanowire superlattices

The electronic properties of strained InAs/GaAs nanowire superlattices are computed using a semi-empirical sp3d5s* tight-binding model, taking strains, piezoelectric fields and image charge effects into account. Strain relaxation appears to be efficient in nanowire heterostructures, but is highly inhomogeneous in thin InAs layers. It digs a well in the conduction band that traps the electrons at the surface of the nanowires. This likely decreases the oscillator strength and might ease the capture of the electrons by nearby surface defects.