Quantum-confined Stark effects in semiconductor quantum disks

Quantum-confined Stark effects (QCSE´s) on excitons in semiconductor quantum disks with finite-potential barriers have been calculated as a function of disk size parameters by a variational calculation in an effort to examine possible application to optical devices. The calculations agree with experimental data reported so far. Although the exciton binding energy, E_b, for smaller diameters is large at zero bias, it decreases more with increasing electric field, which is contrary to the E_b behavior in a spherical quantum dot and quantum well. This larger decrease results in a smaller red Stark shift. Both the red Stark shift and the oscillator strength can be controlled by changing disk diameter and height. The analysis shows that favorable QCSE characteristics, i.e., a large red Stark shift at a small electric field with large oscillator strength, can be obtained