Surface manipulation and characterization of compound semiconductors using electrochemical ultra-high vacuum techniques
Ward, Lindell Carl
MetadataShow full item record
The formation of compound semiconductors by electrochemical methods is an important area of research for materials science. Electrochemical Atomic Layer Epitaxy (EC-ALE) provides a technique to produce compound semiconductors at room temperatures and pressures. This technique uses an electrochemical phenomenon called underpotential deposition (UPD) to grow these materials one atomic layer at a time. These UPD processes must be investigated by surface analysis techniques. The UPD of antimony on the low-index planes of copper was studied using ultra-high vacuum electrochemistry (UHV-EC) techniques. Antimony was deposited from acidic chloride solutions and then analyzed by surface science methods. This analysis revealed an UPD process did occur for the electrodeposition of antimony onto copper single crystal substrates. The antimony coverages and structures varied with the deposition potential for each of the low-index planes of copper. Gallium arsenide single crystal substrates were studied by surface analysis techniques. The GaAs crystals were to be chemically prepared to be used as substrates for compound semiconductor electrodeposition. This would produce a semiconductor heterojunction by EC-ALE. These GaAs samples were treated with various chemical etches to remove any contamination or damaged layers. Electrochemically-assisted etches were applied to the samples. Individual electrochemical treatments were developed to remove either gallium or arsenic from the surface. This gives a method for removing excess gallium and arsenic from the sample.