Quasicrystals, materials with aperiodic long-range order, have been found in intermetallics, soft materials such as colloids and supermolecules, and also in two-dimensional monolayer films. Here we present the first example of three-dimensional growth of a single-element quasicrystalline film. Using a hitherto unexplored template, the icosahedral Ag-In-Yb quasicrystal, and various experimental techniques combined with theoretical calculations of adsorption energies, we find that lead atoms deposited on the surface occupy the positions of atoms in the rhombic triacontahedral cluster, the building block of the substrate, and thus grow in layers with different heights and adsorption energies. We show that the adlayeradlayer interaction is crucial for stabilizing this epitaxial quasicrystalline structure. The finding opens an avenue for further investigation of the impact of the aperiodic atomic order over periodic order on the physical and chemical properties of materials.

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Solar cells often capture the public's attention and are a source of fascination to students (Hamakawa 1987, Zweibel 1990). We have found it profitable to tap this interest in solar cells by introducing students at an early stage of their undergraduate curriculum to the rudiments of photovoltaic devices. The purpose of this article is to describe a very simple experiment that allows college students in introductory physics courses to plot the I-V characteristics of a solar cell, and hence measure important photovoltaic parameters, such as the fill factor (E) and light conversion efficiency. A simple solar cell experimentThe following experiment was performed using a commercial polycrystalline silicon solar cell with an active area of 8.5 cm X 8.5 cm. Under illumination from an artificial light source with an intensity of 8.4 mW the short-circuit current -I V I