Chemistry Reference
In-Depth Information
Figure 2.8 shows the concentrations of each dissolved species in various mixtures of
solutions.
142
solutions with higher pH values can be made
634
by adding
the presence of other species as shown in Table 2.6.
to the system.
The solubility of silicon may also be affected by
2.3. SURFACE ADSORPTION
The atoms of the very first surface layer have unsaturated bonds, the so-called
dangling bonds, due to the disruption of the periodicity of the crystal structure at the
surface. These atoms are highly unstable and react rapidly with the chemical species
in the environment, particularly oxygen and water, to form a chemically more stable
layer which passivates the surface. In air the silicon surface tends to react with oxygen
forming a thin oxide film, that is, native oxide. In water and aqueous solutions the
surface of silicon can be terminated by various species including hydrogen, hydroxyl,
fluorine, and oxide. In addition, a silicon surface, depending on cleaning procedures,
