Chemistry Reference
In-Depth Information
1
Basic Theories of Semiconductor
Electrochemistry
1.1. INTRODUCTION
Silicon, due to its importance in the electronics industry, is perhaps the most investi-
gated electrode material in the field of semiconductor electrochemistry. A wide range
of electrode phenomena, from electropolishing to formation of porous silicon as well
as from current multiplication to current oscillation, can occur on silicon electrodes.
As will be seen in later chapters, many details of these phenomena are not directly
explicable by the existing theories of semiconductor electrochemistry. This is perhaps
related to the fact that the basic theories deal with idealized situations, but the electrode
behavior of a specific system almost always deviates from the ideal situations in
different ways. Also, the rich details of each large-scale phenomenon, e.g., formation
of porous silicone are determined by a set of reactions that are intrinsically complex at
the atomic scale such that the rich details are lost when simplifications are made in a
theory. However, the basic concepts and theories can still be useful in describing the
electrode processes at certain temporal and spatial scales and the large-scale phe-
nomena can be understood by taking into account the different aspects and scales of
these processes.
This chapter provides an overview of the various aspects of semiconductor elec-
trochemistry, which will be useful in describing the specific phenomena on silicon elec-
trodes in later chapters. Also, this systematic description of the basic theories is intended
to be used as a reference base, on which the details of electrode behavior in different
situations are characterized and organized. To avoid unnecessary detail and use of
space, the descriptions in this chapter are limited to the basic concepts, the physical
schemes, and the essential quantities and equations that are required to understand
these concepts and schemes. More detailed treatment of the various aspects of semi-
conductor electrochemistry can be found in the literature.
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