DETERMINATION OF SILVER COVERAGE ON SI(111) 3X1 (6X1)-AG SURFACES

The number of silver atoms incorporated into a Si(111)3 X 1(6 X 1)-Ag structure is determined by scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). Silver MNN Auger intensities from surfaces with two different compositions were compared between clean 7 X 7, (square-root 3 X square-root 3)R 30-degrees-Ag, and 3 X 1(6 X 1)-Ag structures, which were determined from scanning tunneling microscopy images. From the AES intensity ratio and known occupancies of each reconstruction, the number of Ag atoms incorporated into the 3 X 1(6 X 1)-Ag structure was determined to be 0. 36+/-0.16 ML. This value is close to 1/3 ML, suggesting that one of the two rows observed by STM does not consist of Ag atoms.