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

用场离子显微镜(FIM)研究了W、Ta、Mo和Nb衬底表面的原子状态和Pd超薄层的生长以及氢与Pd单层膜的相互作用。在Pd-衬底界面观察到的Pd附着层是最稳定的，形成了假象结构。当形成假晶态Pd单分子膜时，功函数出现极大值。在W(011)、Ta(011)、Mo(011)和Nb(011)衬底上生长的Pd单层的脱附场强度分别为52V/nm、46V/nm、44V/nm和39V/nm。这些值强烈地依赖于衬底原子的蒸发场。还研究了在Ta和Mo表面上生长的Pd本征覆盖层及其原子态。从FIM图像和脱附场强可以清楚地区分Pd覆盖层和稳定的伪晶Pd层的原子态的不同。当在衬底(011)面上沉积Pd20-30原子层时，发现了Pd(111)*Mo(011)和Pd(111)*Ta(011)的晶体取向。还研究了氢与W(011)和Mo(011)表面Pd单分子膜的相互作用，并观察到脱附场强度随氢的增加呈指数衰减。分析了Pd赝晶单分子膜在Mo(011)表面的热表面扩散过程。

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.