Influence of manganese contamination on high-mobility GaAs/AlGaAs heterostructures

TL;DR

This study investigates how manganese contamination affects the electron mobility and optical properties of GaAs/AlGaAs heterostructures, demonstrating that high mobility can be maintained even with Mn presence during growth.

Contribution

It provides evidence that high-mobility GaAs/AlGaAs heterostructures can be grown in the same chamber as GaMnAs layers without compromising electron mobility.

Findings

Mn contamination reduces electron mobility significantly.

Distinct photoluminescence band appears with Mn contamination.

High mobility structures reach 5.4 x 10^6 cm^2/Vs despite Mn presence.

Abstract

Photoluminescence and magnetotransport measurements have been performed to assess the quality of modulation doped GaAs/AlGaAs heterostructures. The temporal evolution of the low-temperature electron mobility of samples prepared in a molecular beam epitaxy chamber containing manganese as a source material was studied. Mn contamination was identified to be responsible for the reduction of the electron mobility to 1 x 10^{6} cm^{2}/Vs and the appearance of a distinct photoluminescence band. In contrast, structures in which this signal is absent reach mobility values of 5.4 x 10^{6} cm^{2}/Vs. This directly proves that the epitaxy of high-mobility electron systems and structures containing GaMnAs layers, in principle, can be combined in one growth chamber.