Stability of semiconductors

Primarily connected to corrosion concepts, Pourbaix diagrams may be used within the scope of prediction and understanding of the thermodynamic stability of materials under various conditions. Park and Barber [25] have shown this relevance in examining the thermodynamic stabilities of semiconductor binary compounds such as CdS, CdSe, CdTe, and GaP, in relation to their flat band potentials and under conditions related to photoelectrochemical cell performance with different redox couples in solution. 

Park SM, Barber ME (1979) Thermodynamic stabilities of semiconductor electrodes. Electroanal Chem 99 67-75... 

Diaz AF, Logan JA(1980)Electroactive polyanihne films. JElectroanalChem 111 111-114 Noufi R, Nozik AJ, White J, Warren LF (1982) Enhanced stability of photoelectrodes with electrogenerated polyanUine films. J Electrochem Soc 129 2261-2265 Noufi R, Tench D, Warren LE (1981) Protection of semiconductor photoanodes with photoelectrochemicaUy generated polypyrrole films. J Electrochem Soc 128 2596-2599 Jaeger CD, Fan FRF, Bard AJ (1980) Semiconductor electrodes. 26. Spectral sensitization of semiconductors with phthalocyanine. J Am Chem Soc 102 2592-2598 Gerischer H (1977) On the stability of semiconductor electrodes against photodecomposition. J Electroanal Chem 82 133-143... 

As already mentioned in the introduction, various fundamental and many empirical results have been published. Although photoelectrochemical cells are easily made, many problems concerning the stability of semiconductors and the function of catalysts still remain to be solved. There are few other approaches such as for instance sensitization (see e.g.) which are not treated here. In addition it should be mentioned that photoelectrochemical systems have been used for light induced synthesis of organic compounds (see e.g.) which could also not be considered in this article. 

Gerischer H (1977) On the stability of semiconductor electrodes against photodecomposition. J Electroanal Chem 82 133-143... 

The stability of semiconductor electrodes, their resistance to photocorrosion, become an especially urgent problem in connection with ever-extending photoelectrochemical applications of semiconductors. This refers, first of all, to electrodes of photoelectrochemical cells for solar energy conversion. 

Study the stability of semiconductor materials and coatings for protection against corrosion. 

Figure 12. Control of electron transfer reactions at semiconductor solution interfaces (a) electron transfer at a semiconductor solution interface and degradative recombination processes (b) application of charged colloid as a supporting agent of semiconductor particles (c) application of a redox functionalized polymer as a supporting matrix for stabilization of semiconductor colloids and effective trapping of conduction band electrons.

T. Ikegami, S. Sudo, Y. Sakai Frequency Stabilization of Semiconductor Laser Diodes. (Artech House, Boston 1995)... 

Quasi-Fermi levels are also considered for the description of the stability of semiconductors against photocorrosion, as will be described below. 

In Eq. 28, pEdec and Jzdec denote the anodic and cathodic decomposition energy, respectively. Two concepts are used to describe the stability of semiconductors at the electrolyte contact First, the general thermodynamic stability against corrosion is determined form the position of the semiconductor band edges with respect to the decomposition levels, as shown in Fig. 8. Situations shown encompass complete stability, complete instability, and stability against anodic or cathodic corrosion. 

The scientific accomplishments suggest, however, that other methodologies may be envisaged to expand the area of DNA electronics. The construction of dendritic arrays that include semiconductor nanoparticles, similar to the assembly of the Au nanoparticles, may be envisaged. The photoactivity of the particles may be used to adapt photoelectrochemistry (photocurrents) as the transduction means. The high stability of semiconductor nanoparticles and their intense fluorescence may then be used for the optical detection of DNA. The polymerase-induced replication of the DNA may be performed with redox-functionalized phosphorylated bases. The amperometric responses of the replicated DNAs and... 

The issue of whether a semiconductor alloy is really soluble is essential to the success of its design. Fortunately, reasonable models of solubility exist and can be applied to these materials. The stability of semiconductor alloys can be treated at least approximately with regular solution theory (see Chapter 4), which works well enough to give an idea of the general behavior of alloys including ternary and quaternary systems. 

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