Electron excitation during anodic decomposition of III–V compounds induced by hole injecting species (Ce4+)

Etchéberry, Arnaud; Gautron, Jean-Claude; Khoumri, El Mati; Sculfort, J. L.

doi:10.1016/0022-0728(90)87388-z

Cited by 13 publications

(8 citation statements)

References 17 publications

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“…Etching of samples, preparation of solutions, and electrochemical setup, are described elsewhere (3). All the potentials are expressed with respect to a standard mercurous sulfate saturated K2SO4 reference electrode (denoted MSE-O/MSE = +0.64 V/SHE).…”

Section: Methodsmentioning

confidence: 99%

“…Single crystal n-lnP, GaP, and GaAs with a carrier density of about 1018 cm -3 and a crystallographic orientation <100> were mounted as rotating disk electrodes (3). Etching of samples, preparation of solutions, and electrochemical setup, are described elsewhere (3). All the potentials are expressed with respect to a standard mercurous sulfate saturated K2SO4 reference electrode (denoted MSE-O/MSE = +0.64 V/SHE).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Dissolution Rate of III–V Compound Oxides Influence of Cerium Species

Khoumri

Etchéberry

Poliakoff

et al. 1991

J. Electrochem. Soc.

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In this letter, the blocking effect of the hole injection current observed in the presence of cerium ions after oxidation of various III-V compounds is analyzed. This effect which is only observed in III-P compounds is due to the presence of a complex multiphase film (phosphorus oxides, CePO4).In a previous paper (1), we have reported a weakening and even a blocking effect in the hole injection process proceeding from the reduction of ceric species (Ce 4') in sulfuric acid aqueous solutions. This effect manifests in a decrease of both hole injection and oxidation currents. Anodic current is due to the injection of electrons during the corrosion process of several III-V compounds. It depends on various parameters such as concentration of hole injecting species (Ce 4~) and is only observed after oxidation of indium phosphide (InP) compound.The characteristic variations of the cathodic current saturation level are an internal probe for the eventual modifications of the interface. This current, for an unperturbed surface, obeys Levich's law because the reduction of Ce 4+ ions is a diffusion-limited process (2).The experimental observations do not always correspond to the above-mentioned assertions.The aim of this letter is to describe results observed under similar experimental conditions with different III-V compounds in order to determine the real origin of this effect in the presence of cerium ions. * Electrochemical Society Active Member. I I I i ----_.-_-.,~ / S Ce4+ ICaM / f/V) H2SO 4 0.SM -o.'5 -olo k,. -0.0 \ --0.1 .~ r~ --0.2 ' --0.3 E~ VvsMSE Fig. 1. Voltammogram (J/E) of n-lnP electrode in the presence of redox species Ce 4'. ~ = 36 rad 9 s 1 is the rotation speed of the rotating disk electrode. N corresponds to the number of polarization cycles at a scan rate v = 20 mV 9 s 1. If the polarization range is kept in region I, it is possible to obtain curve N = 1 after several polarization cycles and that confirms the reversibility of the phenomenon. ExperimentalSingle crystal n-lnP, GaP, and GaAs with a carrier density of about 1018 cm -3 and a crystallographic orientation <100> were mounted as rotating disk electrodes (3). Etching of samples, preparation of solutions, and electrochemical setup, are described elsewhere (3). All the potentials are expressed with respect to a standard mercurous sulfate saturated K2SO4 reference electrode (denoted MSE-O/MSE = +0.64 V/SHE). ResultsInP.--The blocking effect observed in n-lnP samples (Fig. 1) consists of a decrease of cathodic and anodic currents as time increases. This effect depends principally on the concentration of Ce 4+ ions and on the level of excitation current. For example it appears clearly in the conditions depicted in Fig. 1.This effect is a reversible process. Thus, if the polarization domain is reduced to region I after perturbation, it is possible to regenerate the initial cathodic current. After a total regeneration, current-voltage curves in region 1 are stable again at all times, and Levich's law is verified again (1).GaP.--A reversible weakening ...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Dissolution Rate of III–V Compound Oxides Influence of Cerium Species

Khoumri

Etchéberry

Poliakoff

et al. 1991

J. Electrochem. Soc.

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“…The slope of the experimental plot is found to be temperature-independent between 280 and 310 K. Considering Eq. [19], this result suggests that neither kc nor .k~ "J is significantly temperature-dependent. As far as k~ is concerned, this would imply that the relevant decomposition intermediates have an energetic position either right underneath or above the conduction bandedge, so that practically no thermal excitation is required for electron injection.…”

Section: Discussionmentioning

confidence: 71%

“…[lc[ = 6. f. kl [I(V)] [17] From the steady-state conditions for X1 it follows that ~ol = 6-r-[~o + k2~} IX1] [18] Hence, the relationship between ja and jr is given by ja = [k~r162 + k~)] " ~Jd [19] Equation [19] predicts Ja to be proportional to ~r as confirmed experimentally (see Fig. 6).…”

Section: Discussionmentioning

confidence: 91%

Electrochemical and Etching Behavior of InP Single Crystals in Iodic Acid Solutions

Vermeir¹,

Goossens²,

Kerchove³

et al. 1992

J. Electrochem. Soc.

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The etch rate of the (100)-face of n-and p-type InP and that of the (111)-and (111)-faces of n-InP in aqueous iodic acid solutions was measured as a function of several variables using a flow-cell setup. The electrochemical behavior of HIO3 at the n-and p-InP electrode was investigated cathodically and anodically, in darkness and under illumination. The limiting photocurrent, both cathodically for p-type as anodically for n-type InP, was found to be enhanced when adding HIO3 to the indifferent electrolyte solution; possible electrode reaction mechanisms are discussed. By combining the etch and electrochemical results, the stoichiometry of the etch reaction was deduced, and it was established that the etch process occurs by a chemical mechanism, involving the formation of radical-type decomposition intermediates, chemical etching was found to compete with anodic etching when holes are available at the surface. A difference in surface morphology after etching was observed between the (111)-face, on one hand, and the (111)-and (100)-faces, on the other hand, although the etch rate was in all cases diffusion-limited. A tentative explanation for this phenomenon is proposed.

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“…22 For j = f(V) curves, they were mounted as rotating disk electrodes as described before (w denotes the electrode rotation speed in rounds per second (rps)). 26 The solutions were deoxygenated by bubbling highpurity Ar, and the reference electrode was a standard mercurous sulfate-saturated electrode, denoted MSE (0 V/MSE = 0.64 V/SHE). The electrochemical apparatus was a classical threeelectrode setup.…”

Section: Methodsmentioning

confidence: 99%