Experimental Determination of the Collection Efficiency of a Metal/n‐Type Semiconductor Rotating Ring‐Disk Electrode

Verney, E.; Martin, J. R.; Cléchet, P.

doi:10.1149/1.2114314

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…N is experimentally determined by a procedure based on temporary metalization of the semiconductor disk (21). All measurements are carried out under potentiostatic conditions in a classical threeelectrode electrochemical cell.…”

Section: Methodsmentioning

confidence: 99%

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Stabilization of n ‐ GaAs in Acidic Concentrated Iodide Electrolytes

Allongue

Cachet

Cléchet

et al. 1987

J. Electrochem. Soc.

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Although n-GaAs is known to be unstable in presence of iodine, it is shown that this semiconductor can be efficiently stabilized by using highly concentrated acidified iodide aqueous solutions. The effects of proton activity and iodine and iodide concentrations on the electrode stability are investigated by means of rotating ring-disk experiments, RHEED observations, and chemical analysis of the electrolyte. Impedance measurements show a positive shift of the bandedges of GaAs with iodine concentration and illumination level. At a nominal pH of 0, the stabilization ratio S is measured close to 100% (80%) for n-GaAs in contact with a 7M (2M) NaI solution, respectively. Under illumination, the I-/I3-redox level is found to be favorably located near midgap. Kinetic analysis of the competing hole reactions yields a satisfactory simulation of S vs. I concentration. The hole capture by reduced species is found to be proportional to the concentration of iodide ions, not to their activity, in contrast to expectation. Furthermore, it is shown that chemisorbed Ru 3+ cations act as a catalyst for hole transfer and thus improve the stability of n-GaAs in 7M NaI solution.) unless CC License in place (see abstract).ABSTRACT A general mathematical model for studying the kinetics of electrochemical reactions at a rotating disk electrode under steady-state potentiostatic conditions is presented. The model, apart from predicting the net and partial current densities at given values of the applied potential, the ohmic potential drop, and the concentration and potential profiles in the solution, also accounts for homogeneous reactions of any order in the solution and noncharge transfer reactions at the electrode surface. The versatility of the model is demonstrated by the application of the model to a variety of complex reaction schemes.

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Section: Methodsmentioning

confidence: 99%

“…The ring is made with gold or platinum. N is experimentally determined by a procedure based on temporary metalization of the semiconductor disk (21). The stabilization ratio S of the n-type semiconductors is defined as the fraction of the total photocurrent, Iph, corresponding to the oxidation of the reduced species.…”

Section: Methodsmentioning

confidence: 99%