Formation of arsenic sulfide on GaAs surface under illumination in acidified thiourea electrolytes
المؤلف | Khader, Mahmoud M. |
المؤلف | Aljaber, Amina S. |
تاريخ الإتاحة | 2024-03-25T06:42:37Z |
تاريخ النشر | 2011 |
اسم المنشور | Applied Surface Science |
المصدر | Scopus |
الرقم المعياري الدولي للكتاب | 1694332 |
الملخص | The present article reports the formation of arsenic sulfide films on GaAs by the potentiodynamic polarization in acidified thiourea (TU) electrolytes under photo-illumination. Oxidation of TU competes with the oxidation of GaAs itself and leads to the formation of surface arsenic-sulfide films. Surface chemical composition is investigated by X-ray photoelectron spectroscopy (XPS), demonstrating the formation of As-sulfide as the XPS peaks at binding energies of 42.6 and 162.5 eV for As 3d and S 2p, respectively, are observed. XPS results also show diminishing of Ga species from the surface while As-sulfide is forming. Though, As-sulfide is predominantly formed on the surface, but the inductive coupling plasma-mass spectroscopy (ICP-MS) analysis still shows a preferential dissolution of As ions into electrolytes. These results indicate that Ga ions diffuse into the bulk of the electrode material. The formation of As-sulfide, initially, enhances the photocurrent generation; presumably, due to suppressing electron-hole recombination processes. Further deposition of As-sulfide deteriorates GaAs photoactivity due to retarding light absorptivity because of depositing a thick As-sulfide film. The morphology of the As-sulfide film is characterized by scanning electron microscopy (SEM) that shows the formation of smooth and nonporous films in TU electrolytes acidified by H2SO4 of concentration ≥0.2 M. Electrochemical impedance measurements show that GaAs corrosion is limited by the growth and oxidation of the sulfide layer. |
راعي المشروع | The authors would like to thank the Qatar National Research Fund (QNRF) for supporting this research through the Undergraduate Research Experience Program, project number UREP 07 - 006 - 1 - 002 for the year 2010. The authors also wish to thank professor Jan Kwak for valuable discussion and revising the manuscript. We are also grateful to Dr Dan Graham at the Surface Analysis Recharge Centre, Department of Bioengineering, University of Washington, Seattle, USA for doing and analysing the XPS experiments. |
اللغة | en |
الناشر | Elsevier |
الموضوع | As-sulfide Corrosion GaAs Impedance XPS |
النوع | Article |
الصفحات | 68-75 |
رقم العدد | 1 |
رقم المجلد | 258 |
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