FIELD IONIZATION OF GASES AT A METAL SURFACE AND THE RESOLUTION OF THE FIELD ION MICROSCOPE
FIELD IONIZATION OF GASES AT A METAL SURFACE AND THE RESOLUTION OF THE FIELD ION MICROSCOPE
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DOI：
10.1103/physrev.102.624
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发表时间：
1956-01-01
期刊：
影响因子：
--
通讯作者：
BAHADUR, K
中科院分区：
文献类型：
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作者：
MULLER, EW;BAHADUR, K
正离子场致发射的机制被认为取决于分子的供应及其在高达5亿伏/厘米的电场中的电离概率。实验电流场特性与理论曲线相吻合。在减速电位管中测量的速度分布表明，离子起源于表面上方约5至100 A，这取决于场。本文介绍一种简单的质谱计，它采用场发射体作为点离子源。场离子显微镜的分辨率取决于针尖半径，极化率和电离势的气体，并可能上的调节系数和温度。氦的分辨率似乎最好，约为4埃。操作场解吸显微镜具有足够的分辨率，以显示表面的晶格结构的可能性进行了讨论。
The mechanism of field emission of positive ions is considered as depending upon the supply of molecules and their ionization probability in a field up to 500 million volts/cm. Experimental current-field characteristics match the theoretical curves. The velocity distribution, measured in a retarding potential tube, shows that the ions originate some 5 to 100 A above the surface, depending upon the field. A simple mass spectrometer is described which uses the field emitter as a point ion source. The resolution of the field ion microscope is found to depend upon tip radius, polarizability and ionization potential of the gas, and possibly upon the accommodation coefficient and the temperature. Helium seems to give the best resolution of about 4 A. The possibility of operating a field desorption microscope with sufficient resolution to show the lattice structure of the surface is discussed.