QUANTUM STATE DEPRESSION IN A SEMICONDUCTOR QUANTUM WELL

Abstract

In this study, the quantum state depression (QSD) in a semiconductor quantum well (QW) is investigated. The QSD emerges from the ridged geometry of the QW boundary. Ridges impose additional boundary conditions on the electron wave function, and some quantum states become forbidden. State density is reduced in all energy bands, including the conduction band (CB). Hence, electrons, rejected from the filled bands, must occupy quantum states in the empty bands due to the Pauli exclusion principle. Both the electron concentration in the CB and the Fermi energy increased, as in the case of donor doping. Since quantum state density is reduced, the ridged quantum well (RQW) exhibits quantum properties at widths approaching 200 nm. A wide RQW can be used to improve photon confinement in QW-based optoelectronic devices. Reduction in the state density increases the carrier mobility and makes the ballistic transport regime more pronounced in the semiconductor QW devices. Furthermore, the QSD doping does not introduce scattering centers and can be used for power electronics.