A Structural Study of Electrodeposited Fe on n-GaAs(001)

Abstract

The microstructure of Fe films electrodeposited onto n-GaAs͑001͒ from FeCl 2 and FeSO 4 -͑NH 4 ͒ 2 SO 4 electrolytes was examined by X-ray and electron diffraction. Symmetrical -2 X-Ray diffraction from films deposited from chloride solutions indicates a dominant ͑001͒ texture with the presence of additional minority orientations. In contrast, deposition from an ammonium sulfate electrolyte yields films that only exhibit ͑001͒ scattering in the -2 geometry. Transmission electron microscopy ͑TEM͒ crosssectional images of films grown in chloride solutions reveal intermittent cube-on-cube epitaxy that is also evident in plan view TEM dark field images. Interestingly, X-ray pole figure measurements for all specimens examined reveal an additional ͑221͒ orientation that is undetectable by symmetric -2 diffraction. The ͑221͒ oriented material most likely derives from twinning of ͑001͒ oriented grains during growth.

Role of Hydrogen Evolution during Epitaxial Electrodeposition of Fe on GaAs

“…For epitaxial electrodeposition of Fe on GaAs, most often the substrate is immersed electrically "hot", but the underlying mechanism for an improvement has not been conclusively identified. 9,13,17 For the same electrolyte as used in the present study, we recently showed that the electrically "hot" immersion with a potential applied before and during immersion, gives better epitaxial properties according to the FMR results. 17 The role of the hydrogen evolution proposed in the present study can explain this favorable effect: in the case of "hot" immersion, a strong hydrogen evolution and Fe deposition are initiated immediately, and the As-H adsorption layer cannot form during immersion prior to Fe deposition.…”

“…At first glance, this is unexpected, since the opposite, namely lowering |j|, and thereby the growth rate, was suggested as a route for better epitaxy of Fe on GaAs. 9 However, this route has not been experimentally confirmed. In contrast, in experiments in the systems Au/Si 22 and Bi/GaAs, 23 an improved epitaxial growth and crystallinity of contacts is achieved when electrodeposition takes place at or after application of more cathodic E, and thus higher |j|.…”

Interface Magnetism in Ferromagnetic Metal–compound Semiconductor Hybrid Structures

“…Formation of epitaxial Fe contacts to GaAs(001), GaAs (110), and GaAs(111) from a ferrous ammonium sulphate (Fe(NH 4 ) 2 SO 4 ) electrolytic solution by Bao et al 83 , and a comparison between contacts to GaAs(001) using iron chloride (FeCl 2 ) and ferrous ammonium sulphate electrolytes by Svedberg et al 84 , have demonstrated that electrodeposition may also be a useful technique for ferromagnet/semiconductor contact formation. As electrodeposition is a very lowenergy method, the formation of very abrupt interfaces should be possible by this technique 84 56 .…”

“…As electrodeposition is a very lowenergy method, the formation of very abrupt interfaces should be possible by this technique 84 56 . One significant advantage of sputter deposition over MBE growth is the ability to easily apply a magnetic field to the structure during film deposition in order to 'set' a further magnetic anisotropy: in MBE the electronbeam surface analysis tools typically employed to study the surface structure during growth are intrinsically incompatible with such a magnetic 'forming' field.…”

Electrodeposition of Iron and Iron Alloys

“…Iron and iron-nickel alloy deposits have attracted increasing attention as components in spintronics with a semiconductor such as gallium-arsenide (GaAs), where the quality, including preferred orientation and lattice mismatch to the semiconductor is important. [178,179] …”