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.