Articles you may be interested inThe band gap of ultrathin amorphous and well-ordered Al 2 O 3 films on CoAl (100) measured by scanning tunneling spectroscopy J. Appl. Phys. 105, 07C902 (2009); 10.1063/1.3056577 Ultrathin epitaxial Al 2 O 3 films grown on Nb ( 110 ) ∕ sapphire ( 0001 ) investigated by tunneling spectroscopy and microscopy J. Appl. Phys. 97, 083515 (2005); 10.1063/1.1876580 Study of ultrathin Al 2 O 3 /Si (001) interfaces by using scanning reflection electron microscopy and x-ray photoelectron spectroscopy Amorphous SiO films are prepared by radio-frequency planar magnetron sputtering in a background of argon. Inelastic electron tunneling spectra are presented of the films incorporated in AI/SiO/Pb tunnel junctions with the aluminium films pre-or post-oxidized relative to the SiO deposition stage. Both the aluminium and lead junction electrodes are evaporated in a standard oil diffusion pumped, liquid nitrogen trapped vacuum system at a base pressure of 10 -7 Torr; aluminium oxidation is achieved either by admitting oxygen into the vacuum chamber or by performing a low power dc oxygen glow discharge. Spectra obtained are similar, but not identical, to those obtained for evaporated SiO films. Different types of silicon hydride species are observed depending on the environment to which the SiO films are exposed after their deposition. Possible reactions of the films with water vapor are discussed which could produce the observed hydrides which are also assigned. Reverse bias tunneling spectra provide strong evidence that the SiH species reside on the SiO surface, and it is shown that they can be removed by exposure of the surface to a gaseous glow discharge. Atomic force microscopy images are presented of SiO films supported on aluminium and alumina which indicate that their topography is not noticeably modified by exposure to the glow discharge, and that they possess a relatively uniform quasi two-dimensional island structure.

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An easily realized inelastic electron tunneling spectrometer (IETS) controlled by computer through an IEEE-488 interface bus is described. Components and circuits of the system are described in detail in order to help newcomers to IETS build a research quality spectrometer on a relatively low budget. The system design is much simpler and easier to implement than others reported in the literature, and experimental results indicate that the spectrometer has comparable resolution and signal-to-noise ratio. Additionally, in-house software routines offer the system considerable flexibility in spectral data manipulation, for example, background correction, numerical differentiation, and subtraction of one spectrum from another may be performed.

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