Quantum size effect detected by work function measurements during indium deposition on polycrystalline, texturized gold substrate

Abstract

During indium deposition at 77K on a polycrystalline and texturized gold layer ((111) planes parallel to the sample surface) the work function change, δW s, was detected by means of two independent methods allowing the measurement during the deposition: (a) a modified Kelvin method using an oscillating pendulum in a plane parallel to the sample surface; (b) an electron beam diode method, the sample being the anode: in order to minimize the band structure effect, the variations of transmitted current through the metallic bilayer was measured at the lower energy part of I–V curve close to the onset of current flow. In both cases, after an initial rapid decrease of δW s (≈ 1 eV for less than three atomic layers) damped oscillations with a period of about 1.1 nm are observed. These results can be explained by the transverse quantization of electron states in indium layers and by the monoatomic layer-by-layer growth of indium on (111)gold crystal substrate.