Effect of Lateral Electric Field on the Transition Energies of Heavy Hole State and Light Hole State in a Semiconductor Quantum Dot

Abstract

Using effective mass approximation, this study theoretically investigated how the ground state of the valence band in an inverse parabolic quantum dot (IPQD) reaches the light hole state by strengthening the confinement in the QD plane through the application of a lateral electric field on IPQDs. We calculated the exact analytical solution in the form of the Heun function associated with a complex eigenvalue for the degenerate and excited energy states of the electron, light hole (LH), and heavy hole (HH), in the IPQD context. Our results showed that, for a large QD size, the inverse parabolic quantum confinement (IPQC) potential removed the electron and hole degeneracy, while in the strong confinement region (small QD size), crossing occurred. In addition, the results offered another way of switching the ground state energy of the valence band inside QDs from the HH to LH state when applying a lateral electric field on a QD with an IPQC potential. Consequently, different optical transitions were established, and from the lateral electric field, we obtained a larger quantum Stark shift in IPQD compared with the parabolic QD (PQD), and the excited state energies showed a linear Stark shift in both the QDs.