Manganese-diffusion-induced n-doping in semiconductor structures containing Ga(Mn)As layers

TL;DR

This study demonstrates that Mn diffusion from ferromagnetic Ga(Mn)As layers induces n-type doping and enhances electron spin coherence in adjacent quantum wells, impacting spintronic device design.

Contribution

It reveals Mn backdiffusion causes n-doping and increased spin dephasing time in quantum wells near ferromagnetic layers, a novel insight for spintronics.

Findings

Mn diffuses into quantum wells, causing n-type doping.

Mn diffusion increases electron spin dephasing time.

Photoluminescence quenching indicates Mn presence in QWs.

Abstract

Semiconductor structures using ferromagnetic semiconductors as spin injectors are promising systems for future spintronic devices. Here, we present combined photoluminescence (PL) and time-resolved magneto-optical experiments of a nominally nonmagnetic quantum well(QW) separated by a thin barrier from a ferromagnetic Ga(Mn)As layer. Due to the partial quenching of the PL, we conclude that there is a significant Mn backdiffusion into the QW. Moreover, from the time-resolved measurements, we infer that the Mn leads to n-type doping within the QW, and, in addition, strongly increases the electron spin dephasing time.