Semiconductors and their surfaces

The Fermi level, defined as the energy at which the chemical potential of electrons in the solid is zero, is also the principal reference level for the solid at which the binding energy of an electron is zero. This means that an electron at the Fermi energy is not bound to any particular atomic core and is free to move about the solid. Additional energy, called the workfunction, is needed to remove the electron from the solid and is 

Mineral Name Formula Band Gap (eV) Log Resistivity (Qm) Some Observed Conductivity Types 

This general description is incomplete for several reasons. Electrons also redistribute at the interface, leading to an additional means of achieving decreases in the surface 

The reactivity of the surface with respect to heterogeneous redox reactions is often significantly altered by the presence of surface states. The highest occupied states at the 

For the semiconductor, the Fermi level may be located with respect to the vacuum level by the workfunction (( )). The workfunction is defined for any solid phase as the energy difference between an electron at the Fermi level in the solid and the vacuum level (Fig. 7). Although it is defined independent of the location of the removed electron (i.e., bulk vs. surface), when it is experimentally measured there are specific surface contributions to (j) that arise from the fact that an electron at the Fermi level will interact with the particles in the solid as it is removed. This interaction continues well outside the solid and is sensitive to the surface structure and charge distribution, causing (j) for any 

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Information concerning the physics of semiconductors and their surfaces can be found, for example, in References 3 and 4 general problems of electrochemistry of semiconductors are discussed in References 1, 5, and 6. Finally, all these problems are considered in greater detail in a monograph of the authors. ... 

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