Lithium-Doped Germanium Nanowire? Experimental and Theoretical Indication

Abstract

We report a combined experimental and theoretical study of lithium-doped germanium clusters. The doped germanium clusters are produced using a dual-laser dual-target vaporization source and subsequently analyzed using a reflectron time-of-flight (RTOF) mass spectrometer. The RTOF mass spectrum showing the relative abundance of the GenLim clusters, photoionized by an ArF laser, is subjected to a detailed theoretical investigation within the framework of the most popular density functional theory formalism. The periodic appearance of the peaks corresponding to Ge9Li4−5, Ge18Li5−7, Ge27Li9−12, Ge36Li13−16, and Ge45Li16−21 in the mass spectrum clearly suggests the existence of the Ge9 building blocks, which is well-known for the group 14 elements. On the basis of our complementary theoretical investigation, we were able to propose a theoretical model which rationalizes the experimental spectrum. Our systematic theoretical investigation supports the fact that doping with lithium atoms enhances the stability of the Ge cluster, where the Li atom mainly acts as charge balancer. We report for the first time the presence of oligomers of [Ge9]x— units in a gas-phase experiment.