Indium phosphide , surface

Matovu, J.B., et al., 2013h. Use of multifunctional carboxyhc acids and hydrogen peroxide to improve surface quality and minimize phosphine evolution during chemical mechanical pohshing of indium phosphide surfaces. Ind. Eng. Chem. Res. 52, 10664—10672. 

Deposition and etching of Si can be accomplished at line widths <0.4 Jim (204). Practical applications of this laser microchemical processing include ohmic contact formation on p-InP (p-type indium phosphide) and hard-surface-mask repair (205). Further details on recent applications of this process can be found (204-206). 

Bertrand and Fleischer (38) have studied the chemical deposition of silicon dioxide on Indium phosphide. They found that on unoxldlzed, etched surfaces, oxide coverage was "always patchy". If the InP had a monolayer of chemisorbed oxygen, an approximately 60A-thlck oxide film could be formed at room temperature through the formation of Sl-O-P bonds at the Interface. 

Indium phosphide has been a successful material in the preparation of solid-state, photovoltaic, and photoelectrocatalytic electrochemical solar cells [237-240]. Photovoltaic soUd-state solar cells reach single-junction efHciencies above 24% [237]. When used as a photocathode in photoelectrochemical solar energy conversion, the material has shown excellent stability [239], related to the unique surface chemistry of the polar InP(lll) A-face that exposes In atoms only [240]. The photoelectrochemical conditioning of single-crystalline p-type InP with the aim of preparing efficient and stable photoelectrochemical solar cells for photovoltaic and photoelectrocatalytic operation is described in the following and the induced surface transformations are analyzed employing a variety of surface-sensitive methods. 

In chemical vapour deposition a mixture of the gaseous reactants is passed over a solid surface, under such conditions that the reaction will take place at the surface only. Well known examples are reactions for the formation of epitaxial silicon, e.g., by reduction of silicon tetrachloride with hydrogen, or by the decomposition of silane (silicium hydride). Also semiconductor compounds such as gallium arsenide and indium phosphide are produced in a similar manner. This is a very specialized area, a description of which is outside the scope of this book. Nevertheless, chemical vapour deposition is an interesting principle for manufacturing solid materials that might find broader application, so that a brief introduction may be useful here. 

An evidence for a new passivating indium rich phosphate prepared by UV/O3 oxidation of indium phosphide, InP, is provided in Ref [174], The phosphate does not exist as crystal compound and its composition is InPgj02 75. The passivating ability of the latter with respect to InP surface is discussed. 

While the spatial resolution of AES, XPS and SIMS continues to improve, atomic scale analysis can only be obtained by transmission electron microscopy (TEM), combined with energy dispersive X-ray spectroscopy (EDX) or electron energy loss spectroscopy (EELS). EDX detects X-rays characteristic of the elements present and EELS probes electrons which lose energy due to their interaction with the specimen. The energy losses are characteristic of both the elements present and their chemistry. Reflection high-energy electron diffraction (RHEED) provides information on surface slmcture and crystallinity. Further details of the principles of AES, XPS, SIMS and other techniques can be found in a recent publication [1]. This chapter includes the use of AES, XPS, SIMS, RHEED and TEM to study the composition of oxides on nickel, chromia and alumina formers, silicon, gallium arsenide, indium phosphide and indium aluminum phosphide. Details of the instrumentation can be found in previous reviews [2-4]. 

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