Accession Number : AD0623174

Title :   STUDY OF SURFACE PROPERTIES OF ATOMICALLYCLEAN METALS AND SEMICONDUCTORS. PART 1. STUDY OF CDS SURFACES BY LEED. PART 2. COMBINED LEED AND MASS SPECTROMETER MEASUREMENTS FOR ADSORPTION AND CATALYSIS.

Descriptive Note : Progress rept. no. 7, 1 Jan-30 Jun 65,

Corporate Author : BROWN UNIV PROVIDENCE R I

Personal Author(s) : Farnsworth,H. E. ; Cambell,B. D. ; Onchi,M.

Report Date : JUL 1965

Pagination or Media Count : 29

Abstract : The (000/1) MATTE natural growth surface of a vapor grown CdS crystal which had not been polished or etched was studied. It was not possible to obtain a clean surface by heating alone because of contamination from the bulk. Ion bombardment and annealing produced (10/1/4) planes as was found on previously studied crystals. Oxygen adsorption studies of the (000/1) MATTE surface, after using Ga-In eutectic to make contact to the crystal mount, were made. However, the magnitude of these changes was not reproducible. Oxygen adsorption studies of the (0001) SPECULAR surface with no Ga-In contact revealed that photoassisted adsorption occurred. The change in surface potential was approximately directly proportional to the change in oxygen coverage as estimated from decreases in diffraction pattern intensities. This indicates that the oxygen forms negative surface states. The system involving a combination of LEED and quadrupole mass spectrometer was assembled and tested with self oxidation of CO on a (100) nickel crystal surface. (The diagonal mark (1) is here used to indicate the rotation-inversion axis).

Descriptors :   (*SEMICONDUCTORS, SURFACE PROPERTIES), (*CADMIUM COMPOUNDS, SULFIDES), (*NICKEL, SURFACE PROPERTIES), CRYSTAL GROWTH, PURIFICATION, ION BOMBARDMENT, HEAT TREATMENT, OXYGEN, ADSORPTION, PHOTOELECTRIC EFFECT, X RAY DIFFRACTION, CATALYSIS, CARBON COMPOUNDS, MONOXIDES, MASS SPECTROSCOPY

Distribution Statement : APPROVED FOR PUBLIC RELEASE