AVS 52nd International Symposium
    Applied Surface Science Friday Sessions
       Session AS-FrM

Paper AS-FrM6
X-ray Photoelectron Spectroscopic Study of an Oxygen-doped Zinc Sulfide Surface Using Sample Biasing

Friday, November 4, 2005, 10:00 am, Room 206

Session: Practical Methods and Applications for Surface Analysis
Presenter: Y.-Q. Wang, Oklahoma State University
Authors: Y.-Q. Wang, Oklahoma State University
P.M.A. Sherwood, Oklahoma State University
Correspondent: Click to Email
X-ray photoelectron spectroscopy (XPS) was used to study the surface chemistry of zinc sulfide (ZnS) exposed to a number of oxidation treatments at various conditions to understand the effect of oxygen on surfaces of II-VI compounds. These compounds are widely used as luminescence and window materials, where the mechanism of the effect of oxygen interaction and its effect on the properties and applications of these materials, has not been clearly understood. The oxygen was introduced onto the ZnS surface by heat-treating the sample in a furnace with water vapor and by synthesis of ZnS. The core XPS studies were conducted with and without the application of a sample bias potential, and showed that oxygen interaction caused a considerable change in the surface chemistry of ZnS. The application of a positive bias led to a shift in the core XPS peaks expected for a conductive material, but the negative bias gave rise to unusual behavior. In the case of ZnO the core XPS peaks behaved in the way expected of a conducting material under positive or negative bias. The ZnS samples exhibited a peak shift that was closely related to the oxygen content in the surface region. Furthermore, the sample synthesized in aqueous solution resulted in peak splitting under a negative bias. The surface chemistry monitored by XPS, and the interpretation of the biasing shifts allows for a better understanding of the change of luminescence phenomena in ZnS materials involving oxygen.