Crystal orientation effects on the piezoelectric field of strained zinc-blende quantum-well structures

A three-layered zinc-blende quantum-well structure is analyzed subject to both static and dynamic conditions for different crystal growth directions taking into account piezoelectric effects and lattice mismatch. It is found that the strain component S(zz) in the quantum-well region strongly depends on the crystal growth direction and that a piezoelectric strain contribution exists in zinc blende as in wurtzite, albeit smaller. It is also found in the absence of loss effects that resonance frequencies, giving large strains in the structure, depend strongly on the crystal growth direction. Due to the higher symmetry of the zinc-blende structure, we find in a one-dimensional model that piezoelectric effects do not affect strain values for zinc-blende structures grown along the [001] direction in contrast to the corresponding wurtzite result. However, zinc-blende structures grown along a general crystal direction show important changes in strain and the electric distribution due to piezoelectric effects. The findings indicate the quantitative importance of a fully coupled model even for zinc blende, in particular when discussing electronic band structure and optoelectronic properties.