Manipulation of electrical and ferromagnetic properties of photo-sensitized (Ga,Mn)As

TL;DR

This study demonstrates that dye-molecule adsorption and light exposure can modulate the magnetic and electrical properties of (Ga,Mn)As, paving the way for light-controlled magnetic-semiconductor/dye hybrid devices.

Contribution

It introduces a novel method of manipulating (Ga,Mn)As properties using dye molecules and light, showing potential for optically controlled spintronic applications.

Findings

Adsorption of fluorescein lowers Curie temperature and increases resistance.

Light exposure shifts Curie temperature higher and reduces coercive field.

XPS spectra indicate hole quenching at the dye-(Ga,Mn)As interface.

Abstract

We present the manipulation of magnetic and electrical properties of (Ga,Mn)As by the adsorption of dye-molecules as a first step towards the realization of light-controlled magnetic-semiconductor/dye hybrid devices. A significant lowering of the Curie temperature with a corresponding increase in electrical resistance and a higher coercive field is found for the GaMnAs/fluorescein system with respect to (Ga,Mn)As. Upon exposure to visible light a shift in Curie temperature towards higher values and a reduction of the coercive field can be achieved in photo-sensitized (Ga,Mn)As. A mayor change in the XPS spectrum of (Ga,Mn)As indicates the appearance of occupied levels in the energy range corresponding to the (Ga,Mn)As valence band states upon adsorption of fluorescein. This points towards a hole quenching effect at the molecule-(Ga,Mn)As interface which is susceptible to light exposure.