Semiconductor-electrolyte interfaces

Figure Bl.28.10. Schematic representation of an illuminated (a) n-type and (b) p-type semiconductor in the presence of a depletion layer fonned at the semiconductor-electrolyte interface.

Zegenhagen J, Kazimirov A, Scherb G, Kolb D M, Smilgies D-M and Feidenhans l R 1996 X-ray diffraction study of a semiconductor/electrolyte interface n-GaAs(001)/H2S04( Cu) 1996 Surf. Sc/. 352-354 346-51... 

Figure 12. Energy diagram of a semiconductor/electrolyte interface showing photogeneration and loss mechanisms (via surface recombination and interfacial charge transfer for minority charge carriers). The surface concentration of minority...

The reason for the exponential increase in the electron transfer rate with increasing electrode potential at the ZnO/electrolyte interface must be further explored. A possible explanation is provided in a recent study on water photoelectrolysis which describes the mechanism of water oxidation to molecular oxygen as one of strong molecular interaction with nonisoenergetic electron transfer subject to irreversible thermodynamics.48 Under such conditions, the rate of electron transfer will depend on the thermodynamic force in the semiconductor/electrolyte interface to... 

Jaegermann, W. The Semiconductor/Electrolyte Interface A Surface Science Approach 30... 

Semiconductor-electrolyte interface, photo generation and loss mechanism, 458 Semiconductor-oxide junctions, 472 Semiconductor-solution interface, and the space charge region, 484 Sensitivity, of electrodes, under photo irradiation, 491 Silicon, n-type... 

Boddy PJ (1965) The structure of the semiconductor-electrolyte interface. J Electroanal Chem 10 199-244... 

The diffuse charge distribution in the semiconductor s surface layer leads to a drastically lower cell capacitance at the semiconductor-electrolyte interface. Typical... 

Fig. 3a—c. Charge transfer processes at semiconductor-electrolyte interface a) and b) under forward bias. 

Between 0.20 and 0.30 V, a decay of the initial photocurrent and a negative overshoot after interrupting the illumination are developed. This behavior resembles the responses observed at semiconductor-electrolyte interfaces in the presence of surface recombination of photoinduced charges [133-135] but at a longer time scale. These features are in fact related to the back-electron-transfer processes within the interfacial ion pair schematically depicted in Fig. 11. 

Equation (45) resembles the generalized expression of IMPS for semiconductor-electrolyte interfaces [149,164]. This similarity between the dynamic photoresponses for both types of interfaces is only valid in phenomenological terms, as the natures of the... 

R. H. Wilson, in Photo-Effects at Semiconductor-Electrolyte Interfaces (A. E. Nozik, ed.), ACS Publishers, Washington DC, 1981. 

The basic difference between metal-electrolyte and semiconductor-electrolyte interfaces lies primarily in the fact that the concentration of charge carriers is very low in semiconductors (see Section 2.4.1). For this reason and also because the permittivity of a semiconductor is limited, the semiconductor part of the electrical double layer at the semiconductor-electrolyte interface has a marked diffuse character with Debye lengths of the order of 10 4-10 6cm. This layer is termed the space charge region in solid-state physics. 

Green, M., Electrochemistry of the semiconductor-electrolyte interface, MAEy 2, 343 (1959). 

Basic properties of semiconductors and phenomena occurring at the semiconductor/electrolyte interface in the dark have already been discussed in Sections 2.4.1 and 4.5.1. The crucial effect after immersing the semiconductor electrode into an electrolyte solution is the equilibration of electrochemical potentials of electrons in both phases. In order to quantify the dark- and photoeffects at the semiconductor/electrolyte interface, a common reference level of electron energies in both phases has to be defined. 

Fig. 5.60 The semiconductor/electrolyte interface (a) before equilibration with the electrolyte, (b) after equilibration with the electrolyte in the dark, and (c) after illumination. The upper part depicts the n-semiconductor and the lower the p-semiconductor...

For a more detailed description of the semiconductor/electrolyte interface, it is convenient to define the quasi-Fermi levels of electrons, eFyC and holes, p p,... 

STS, both in situ and ex situ, is making a major impact in the areas of surface science and electrochemistry, particularly in the study of the semi-conductor/vacuum and semiconductor/electrolyte interfaces. 

Figure 2.40 Schematic representation of the external reflectance cell design commonly employed in in situ IR experiments, if the working electrode is a semiconductor, then the semiconductor/ electrolyte interface can be studied under illumination with, for example, UV light by directing the beam perpendicular to the IR beam, as shown.

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