A quantum well structure is provided that includes two or more quantum well layers
coupled by at least one barrier layer such that at least one of a piezo-electric
field and a pyro-electric field is produced. The quantum well structure is sufficiently
doped to cause a Fermi energy to be located between ground states and excited states
of the coupled quantum well layers. The quantum well structure can be incorporated
into a layered semiconductor to form optical devices such as a laser or optical amplifier.
