Sharp ferromagnet/semiconductor interfaces by electrodeposition of Ni thin films onto n-GaAs(001) substrates

Abstract

We report on the chemical, electrical, and magnetic properties of Ni/GaAs(001) interfaces prepared using electrodeposition. Electrodeposition is an equilibrium process which thus releases much less energy per absorbed atom than other deposition techniques. This allows preparation of chemically sharp interfaces which otherwise show a high degree of reactivity and interdiffusion. This is demonstrated by the example of Ni grown on GaAs(001). Photoelectron spectroscopy shows the absence of surface segregation of substrate material or diffusion into the Ni layer. This is confirmed by the electrical and magnetic properties of the films.

Anisotropy of epitaxial Fe films grown on n-type GaAs by electrodeposition

“…3,4 In order to prevent interface intermixing 5,6 however, suitable surface preparation of the GaAs substrate prior to deposition was required. 7,8 Electrodeposition is an alternative film deposition method which has proven to avoid intermixing due to the low energy character of the deposition process 9 and has also been shown to yield epitaxial metallic films with good structural properties on various SC. 10,11 Iron is usually plated from Fe 2ϩ salts, most often sulfate and/or chloride.…”

Thickness dependence of magnetic anisotropy in thin Ni films electrodeposited onto the (011) and (001) surfaces of n-GaAs

“…In the fitting procedure the saturation magnetization was fixed to the bulk value M s = 484 Oe, assuming thus limited intermixing between the Ni film and GaAs substrate, as discussed in Ref. 5. Note that, strictly speaking, the above analytical approach should be used only for films whose thickness does not exceed the exchange correlation length ͑about 6 nm in Ni͒.…”

“…4͒ films on GaAs, and that the resulting interfaces exhibit limited or no intermixing. 5 Control of the magnetic properties-in particular the anisotropy-of magnetic films on semiconductors is of interest in view of the possible manipulation of the injected spins by external magnetic fields.…”

AFM Studies of Ni Electrodeposits on GaAs

“…Operation of these devices would require the growth of ferromagnetic layers onto semiconductor surfaces forming sharp and epitaxial interfaces, thus allowing the transfer of electrons without spin scattering. As it was shown previously [1], electrodeposition of Ni on GaAs substrates is a very promising system for spin injection, since it allows the preparation of epitaxial layers at room temperature with sharp chemical gradients at the interface. This work intends to investigate the roughness evolution of the Ni electrodeposited layers on GaAs as an additional step for the characterization of this system.…”