Modulation of internal piezoelectric fields in strained-layer superlattices grown along the (111) orientation

Large internal piezoelectric fields are generated when strained‐layer superlattices are grown from III–V zinc‐blende‐structure compound semiconductors. The orientation of these internal fields depends on the components of the strain tensor and, consequently, on the growth orientation of the superlattice. In the usual case of strained‐layer superlattices grown along the [001] axis, the piezoelectric fields vanish. However, the case of strained‐layer superlattices grown along the [111] axis is particularly interesting because the internal piezoelectric fields are parallel to the growth axis and their magnitude typically exceeds 100 kV/cm for lattice mismatches as small as 1%. Therefore, [111]‐oriented strained‐layer superlattices exhibit novel physical properties and present technological opportunities not afforded by commonly grown [001]‐oriented strained‐layer superlattices. The internal strain‐induced fields substantially modify the electronic structure and optical properties of [111]‐oriented strained‐l...