Evaluation of atomic layer at metal-metal interfaces with field ion microscope

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Atomic states and the growth of Pd ultra-thin-layer on W, Ta, Mo and Nb substrate surfaces and a hydrogen interaction with Pd monolayer film have been investigated with field ion microscopy(FIM). The Pd adlayer observed at the Pd-substrate interface is most stable and is formed pseudomorphic structure. When the pseudomorphic Pd monolayer is formed, Work function is shown maximum value. Desorption field strengthes of the pseudomorphic Pd monolayer grew on the W(011), Ta(011), Mo(011) and Nb(011) found to be 52 V/nm, 46 V/nm, 44 V/nm and 39 V/nm, respectively. These values depend strongly on the evaporation field of substrate atom. Pd intrinsic overlayer grown on Ta and Mo surfaces and their atomic states have been also investigated. Difference of the atomic states of Pd overlayer and stable pseudomorphic Pd layer could clearly be distinguished from the FIM images and the desorption field strength. When Pd 20-30 atomic layers were deposited on the substrates (011) plane, the crystal orientation grown of Pd(111)*Mo(011) and Pd(111)*Ta(011) found. Hydrogen interaction with the Pd monolayer on W(011) and Mo(011) surface has also been examined, and the desorption field strength were observed to show an exponential decay with hydrogen increment. Thermal surface diffusion processes of Pd pseudomorphic monolayer on Mo(011) surface were also analyzed.