Quantum state depression in semiconductor quantum well

TL;DR

This paper investigates how ridged geometries in semiconductor quantum wells cause quantum state depression, reducing state density and enhancing electronic and optical properties without introducing scattering centers.

Contribution

It introduces the concept of ridged quantum wells (RQW) and demonstrates their potential to improve carrier mobility and photon confinement in optoelectronic devices.

Findings

Quantum state density reduces in RQWs due to boundary conditions.

RQWs exhibit quantum properties at widths near 200 nm.

Reduced state density enhances carrier mobility and photon confinement.

Abstract

In this study, the quantum state depression (QSD) in semiconductor quantum well (QW) is investigated. The QSD emerge 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 reduces in all energy bands, including conduction band (CB). Hence, electrons, rejected from the filled bands, must occupy quantum states in the empty bands due to Pauli Exclusion principle. Both the electron concentration in CB and Fermi energy increases 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. Wide RQW can be used to improve photon confinement in QW-based optoelectronics 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.