A hydrogen-terminated silicon surface is a chemically passivated silicon substrate whose silicon atoms covalently bonded to hydrogen.
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Preparation
One method is to remove the native oxide (SiO2) thin film by etching in hydrogen fluoride aqueous solution, leaving the surface silicon atoms.
Another method uses a hydrogen-covered atomic force microscope (AFM) tip to avoid damaging the fragile silicon surface.
Properties
Since all surface Si atoms are fully co-ordinated, hydrogen termination leads to enhanced stability in ambient environments, unlike a 'clean surface' having unpassivated surface atoms, or dangling bonds. It is relatively inert and can be handled in air without special care for several minutes.
A hydrogen-terminated silicon surface can be flattened at the atomic level by etching. For example, to etch a hydrogen-terminated silicon(111) surface, ammonium fluoride aqueous solution or boiling water can be used.
Like other silyl groups of organic compounds, the H-Si groups on the surface react with molecules that have terminal unsaturated bonds or diazo groups. The reaction is called hydrosilylation. Many kinds of organic compounds with various functions can be introduced onto the silicon surface by the hydrosilylation of a hydrogen-terminated surface.
Potential applications
One group proposed to use the material to create digital circuits made of quantum dots by removing hydrogen atoms from the silicon surface.