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

利用场离子显微镜（FIM）研究了W、Ta、Mo和Nb衬底表面Pd超薄层的原子态和生长，以及氢与Pd单层膜的相互作用。在Pd-衬底界面处观察到的Pd衬底最稳定，形成伪晶结构。伪晶Pd单层形成时，Work函数达到最大值。在W（011）、Ta（011）、Mo（011）和Nb（011）上生长的伪晶Pd单分子膜的解吸场强分别为52 V/nm、46 V/nm、44 V/nm和39 V/nm。这些值在很大程度上取决于衬底原子的蒸发场。研究了在Ta和Mo表面生长的Pd本征包层及其原子态。通过红外光谱图像和解吸场强可以明显区分钯层和稳定伪晶钯层的原子态差异。当Pd 20-30原子层沉积在衬底（011）平面上时，发现Pd(111)*Mo（011）和Pd(111)*Ta（011）的晶体取向生长。研究了氢与W（011）和Mo（011）表面Pd单分子层的相互作用，并观察到解吸场强随氢的增加呈指数衰减。分析了Pd伪晶单层在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.