Electromodulation spectroscopy

ELECTROMODULATION SPECTROSCOPY OF SEMICONDUCTOR NANOSTRUCTURES III-NITRIDES AND DILUTE NITRIDES... 

Electromodulation spectroscopy of semiconductor nanostructures Ill-nitrides and dilute nitrides (invited).11... 

The most complicated form of Modulation Spectroscopy is electromodulation, since in certain cases it can accelerate the electron-hole pairs created by the light. If the electric field is not too large the quantity AR/Rcan be written as ... 

Apart from the above techniques, the electromodulated reflectance spectroscopy combined with cyclic voltammetry has been utilized by Gaigalas et al. [14] in the investigations of electron transfer between the 2Fe-2S protein putidaredoxin and either bare or bekanamycin-modified Ag electrode. Of the two models considered, the free diffusion model, as compared to the adsorbed layer model, exhibited better concordance with the experimental data. After modification of the Ag electrode with bekanamycin, it exhibited only a small increase in the observed redox reaction... 

The fact that both the COad bands and the CO2 band appeared in the same direction on an nm-Ru/GC electrode illustrates one of the main characteristics of the AIREs. It may be worth noting that the COl band center measured in Figure 11(a) is close to that reported by Lin et al. but is about 15cm lower than the value for CO adsorbed on a massive Ru electrode in CO saturated 0.5 M HCIO4 solution studied by using electromodulated infrared spectroscopy (EMIRS) [50]. It is evident that the appearance of the COb band in the spectrum of the nm-Ru/GC electrode is due to significant enhancement of IR absorption. 

A. V. Rao and J. N. Chazalviel, Chemical trends in the electromodulated infrared vibrational spectroscopy of various silicon/electrolyte interfaces, J. Electrochem. Soc. 134, 2777, 1987. 

F. Ozanam, C. da Fonseca, A. V. Rao, and J.-N. Chazalviel, In situ spectroelectrochemical study of the anodic dissolution of silicon by potential-difference and electromodulated FT-IR spectroscopy, Appl. Spectrosc. 51(4), 519, 1997. 

Bewick and Tuxford " have used ac electromodulation reflectance spectroscopy with square wave modulation (stair case) from a potential in the double-layer range to various potentials in the anodic film range. They report the detection of film formation already at Eu = 0.7 V and that the signal associated with the film formation increases until 1.5 V where it levels off. They conclude that the general features of the wavelength dependence of the reflectance spectrum are determined primarily by the wavelength dependence of the optical properties of the Pt substrate and not by the film. 

The EQCM should always be used as an addition tool, in combination with common electrochemical techniques (such as EIS, chrono-coulometry, electromodulated reflectance spectroscopy, FTIR spectroscopy, and in situ STM and AFM techniques, as may be appropriate), not replacing them. 

T. Amemiya, K. Hashimoto, A. Fujishima, Frequency-resolvedfaradak processes in polypyrrole films observed by electromodulation techniques—electrochemical impedance and color impedance spectroscopies, J. Phys. Chem., 1993,97,16, pp. 4187-4191. 

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