Capping-induced suppression of annealing in Ga(1-x)Mn(x)As epilayers

TL;DR

This study reveals that a thin GaAs capping layer on Ga(1-x)Mn(x)As epilayers suppresses ferromagnetic enhancement from annealing, highlighting the surface's role in defect structure and device integration.

Contribution

It demonstrates that even a few monolayers of GaAs capping can significantly inhibit annealing-induced ferromagnetic improvements in Ga(1-x)Mn(x)As.

Findings

A 10-monolayer GaAs capping layer suppresses ferromagnetic enhancement.

Surface capping influences defect structure and magnetic properties.

Implications for device heterostructure design.

Abstract

We have studied the effects of capping ferromagnetic Ga(1-x)Mn(x)As epilayers with a thin layer of undoped GaAs, and we find that even a few monolayers of GaAs have a significant effect on the ferromagnetic properties. In particular, the presence of a capping layer only 10 monolayers thick completely suppresses the enhancement of the ferromagnetism associated with low temperature annealing. This result, which demonstrates that the surface of a Ga(1-x)Mn(x)As epilayer strongly affects the defect structure, has important implications for the incorporation of Ga(1-x)Mn(x)As into device heterostructures.