Electron microscopy and ebl
The investigation of the morphology, structure as well as elemental composition and crystalline arrangement of nanostructured samples at CNR-INO Brescia is carried out by electron microscopy.
Scanning (SEM) and transmission (TEM) electron microscopy feature are capable of sub-nanometric spatial resolution and the associated imaging/analytical techniques are provide structural and chemical information at the atomic scale. The research activity is based on the high-resolution SEM put into operation in 2004 at SENSOR The SEM is capable of detection of transmitted electrons, thus providing compositional imaging at the nanoscale associated to semi-quantitative EDX elemental analysis. The SEM was also equipped in 2006 with two-independently operated piezo-actuators for manipulation of nanowires and in-situ probing of the electrical conductance of nanostructures. Two recent implementation of the SEM are the Electron Beam Lithography system (RAITH) and the set-up for electron tomography. The former will allow to fabricate miniaturized functional device for testing and characterization, the latter will exploit the integration of the magnifying capability of the microscope to the robust algorithm of three dimensional reconstruction.
TEM measurements are carried out within the SENSOR scientific collaboration with IMM CNR Bologna.
The conventional imaging methods (high resolution and diffraction contrast imaging, electron diffraction, nanoprobe diffraction and EDX analysis) are used for morphological and micro-structural investigation of the materials. The TEM is also equipped with High-Angle-Annular-Dark-Field (HAADF) detector and electrostatic bi-prism for Z-contrast imaging and holography. HAADF allows atomically-resolved imaging of the crystalline lattice and the determination of dopants and impurities; in addition electron holography will provide an accurate measurement of the spatial distribution of electrically-active dopants and their effect on the electrical properties in nanostructures.
Application of electron beam lithography
The electron beam lithography (EBL) system is used for the fabrication of functional devices based on single metal-oxide nanowires. The resolution of this patterning technique allows one to exploit the peculiar electrical features of nanostructured single-crystal nanowires. Prototypes of sensing devices, thermoelectric generators are presently under development and investigation.