Contrast in scanning probe microscopy images of ultra-thin insulator films
نویسندگان
چکیده
The contrast in scanning probe microscopy (SPM) images of ultra-thin CaF2 films epitaxially grown on Si(111) is studied using scanning tunneling microscopy (STM) and scanning force microscopy (SFM). STM images of CaF2/Si(111) exhibit a distinct contrast depending on the bias voltage. While images obtained with positive sample bias voltages show the physical topography of the film, images obtained with negative voltages either do not show CaF2 islands or image them as depressions (contrast inversion) at high negative bias voltages (exceeding -8 V). Using SFM, CaF2 can be distinguished from the underlying Si-CaF interface layer by measuring the dissipation of the cantilever oscillation caused by the contact potential difference between CaF2 and the CaF bilayer.
منابع مشابه
Nano-structural Characterization of Post-annealed ZnO Thin Films by X-ray Diffraction and Field Emission Scanning Electron Microscopy
ZnO thin films were deposited on Si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°C). Dependence of the crystallographic structure, nano-strain, chemical composition and surface physical Morphology of these layers on annealing temperature were studied. The crystallographic structure of films was studied using X-Ray Diffracti...
متن کاملAl Doped ZnO Thin Films; Preparation and Characterization
ZnO is a promising material suitable for variety of novel electronic applications including sensors, transistors, and solar cells. Intrinsic ZnO film has inferiority in terms of electronic properties, which has prompted researches and investigations on doped ZnO films in order to improve its electronic properties. In this work, aluminum (Al) doped ZnO (AZO) with various concentrations and undop...
متن کاملElectrical properties of Al 2 O 3 films for TFEL - devices made with Sol - Gel technology
Thin films of Al2O3 have been deposited on ITO-coated glass substrates by a sol-gel dipcoat process. Aluminium isopropoxide (Al(OC3H7)3) was used as the Al source material. X-ray diffraction measurements show that these films are amorphous. Scanning electron microscopy and atomic force microscopy images of the films have revealed a relatively flat surface with no cracks. The dielectric properti...
متن کاملNano-structural Characterization of Post-annealed ZnO Thin Films by X-ray Diffraction and Field Emission Scanning Electron Microscopy
ZnO thin films were deposited on Si(400) substrates by e-beam evaporation technique, and then post-annealed at different annealing temperatures (200-800°C). Dependence of the crystallographic structure, nano-strain, chemical composition and surface physical Morphology of these layers on annealing temperature were studied. The crystallographic structure of films was studied using X-Ray Diffracti...
متن کاملScanning probe microscopy of organic thin films: Phase transitions of liquid crystal monolayers
Since its conception, the scanning probe microscopy (SPM) has attracted increasing attention as a novel method that provides an outstanding capability for direct visualization of topological features and characterization of the local properties of organic thin films. While imaging mechanisms for organic molecules are still being debated, careful and credible studies have been performed enabling...
متن کامل