Photoluminescence and transport in selectively doped p-GaAs/AlGaAs quantum wells: manifestation of the upper Hubbard band

TL;DR

This study investigates how selective doping in p-GaAs/AlGaAs quantum wells affects the upper Hubbard band, revealing increased binding energies and localization consistent with quantum confinement effects.

Contribution

It demonstrates the occupation of the upper Hubbard band in doped quantum wells and analyzes its energy and localization properties, which differ from bulk behavior.

Findings

Binding energy of A+ states increases with quantum well confinement.

Localization radii of A+ states are comparable to well widths.

Temperature-dependent transport and photoluminescence spectra show quantum confinement effects.

Abstract

By selective doping (Be) of the well and barrier regions of p-GaAs/AlGaAs structures we have realized the situation where the upper Hubbard band (A+ centers) has been occupied by holes in the equilibrium. We studied temperature behavior of the Hall effect, variable range hopping conductivity and the photoluminescence spectra of the corresponding structures. The experimental data demonstrated that the binding energy of the A+ states significantly increases with respect to 3D case and strongly depends on well width (9nm,15nm). The localization radii of the A+ states are of the order of well widths.