Band Alignment of N- and P- Doped InP at Electrolyte and Ultra High Vacuum Junctions: Fundamental Correlation between the Open Circuit Potential Under Illumination and XPS Photopeak Energy

International audienc

Progressive surface passivation of an n-InP semiconductor due to polyphosphazene (PPP) in liquid ammonia

International audienc

Modification of the Electrochemical Behavior of InP Electrodes Induced By Ionic Bombardment: The Case of the Response of the Ce4+/Ce3+ Couple

International audienc

Outstanding Contributions of Liquid Ammonia on III-V Semiconductors (Photo)-Electrochemistry

International audienc

The assets of photoemission to probe the surface physico-chemistry of nanodiamonds

International audienc

Contribution of surface characterization tools in understanding the fine surface chemistry of nanodiamonds (NDs)

International audienc

Molybdène et autres métaux dans les abeilles et pollens.”,

International audienc

Photoelectrochemical passivation of undoped n-InP by ultra-thin polyphosphazene film: Towards a perfect photoanode?

International audienceFor the first time, the photoanodic behavior of undoped n-InP (≈ 1015 atoms.cm−3) is studied in liquid ammonia at low temperature (-55 °C) under atmospheric pressure. Under illumination, the low doping level provides unique conditions to monitor charge transfer at the interface since only photo-generated holes are involved in the passivation mechanism. Specific photoanodic transient phenomena are observed due to the photo-holes availability at the interface which depends on light intensity. Cycle voltammograms differ strongly from the initial ones in the dark. Photo-electrochemical transformations of InP responses are followed by cycle voltammetry for two conditions of illumination; under low and high luminous flux intensity. In spite of a pure photo-holes process for both cases, voltammograms are highly dependent on light intensity while impedance measurements present the same strong modifications. One-volt positive shift of the flat band potential is indeed observed. However, whatever is the luminous flux intensity, a low photo-anodic charge is consumed (≈ 1 mC.cm−2) and the same ultra-thin film of polyphosphazene onto n-InP is shown by XPS analyses. Properties of this new interface is discussed in term of energy diagram and photo-holes transfer ability. Under these experimental conditions used, (J ≤ 100 µA.cm−2 and Q ≈ 50 mC.cm−2), the passivated interface behaves as a photoanode toward ammonia oxidation since the ultra-thin film is maintained onto InP

Use of Molybdenum complexes for the safeguard of the honeybees

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Stoichiometry loss induced by ionic bombardment of InP surfaces: A challenge for electrochemistry combined with XPS

International audienceIndium phosphide (InP) surfaces are greatly affected by ionic bombardment. We investigate the resulting surface perturbation through the use of the complementary analytical techniques of electrochemistry and X-ray photoelectron spectroscopy (XPS). Following bombardment, modifications to the surface were identified by a reduction in the dark open circuit potential in comparison to the pristine state. Through XPS studies, it was found that the sputtered surface was enriched with a metallic-like In contribution, which oxidized upon exposure to air. Cyclic voltammetry measurements confirmed this observation, with initial cathodic features related to an oxidized metallic In-enriched layer on the InP surface. Repeated cyclic voltammetry experiments resulted in the formation of a more In-rich overlayer due to a specific oxidation/reduction phenomenon. This behavior is very similar to that obtained by cathodic decomposition on InP surfaces