Piezoelectric effects in semiconductor heterostructures: applications and consequences

The piezoelectric (PZ) effect in strained semiconductor heterostructures can be used as an additional degree of freedom in designing novel heterostructures with desired optoelectronic properties. After a short review of previous work in the field, we discuss two examples in which the presence of the PZ field is either beneficial or unwelcome. First, we present a wavelength-tunable laser diode whose tuning mechanism is based on the quantum confined Stark effect and we show that the tuning range of the device can be significantly enhanced if the active quantum well contains a PZ field. Next, we discuss the case of nitride heterostructures where unwanted polarization-induced electric fields limit seriously their performance in optoelectronic applications. We show that the use of quaternary nitrides can help circumvent this problem.