No abstract

With the recent advances in the field of nanotechnology, measurement and manipulation requirements at the nanoscale have become more stringent than ever before. In atomic force microscopy, high-speed performance alone is not sufficient without considerations of other aspects of the measurement task, such as the feature aspect ratio, required range, or acceptable probe-sample interaction forces. In this paper, the authors discuss these requirements and the research directions that provide the highest potential in meeting them. The authors elaborate on the efforts toward the downsizing of self-sensed and self-actuated probes as well as on upscaling by active cantilever arrays. The authors present the fabrication process of active probes along with the tip customizations carried out targeting specific application fields. As promising application in scope of nanofabrication, field emission scanning probe lithography is introduced. The authors further discuss their control and design approach. Here, microactuators, e.g., multilayer microcantilevers, and macroactuators, e.g., flexure scanners, are combined in order to simultaneously meet both the range and speed requirements of a new generation of scanning probe microscopes.

Epitaxial MnAs films on GaAs͑001͒ substrates are studied at room temperature and in the completely ferromagnetic state below room temperature with low-energy electron microscopy, x-ray magnetic circular dichroism photoemission electron microscopy, and low-energy electron diffraction. The combination of these techniques shows a clear relation between the two-phase structure of the layers and their magnetic domain structure.

Electrical operation of room-temperature (RT) single dopant atom quantum dot (QD) transistors, based on phosphorous atoms isolated within nanoscale SiO2 tunnel barriers, is presented. In contrast to single dopant transistors in silicon, where the QD potential well is shallow and device operation limited to cryogenic temperature, here, a deep (~2 eV) potential well allows electron confinement at RT. Our transistors use ~10 nm size scale Si/SiO2/Si pointcontact tunnel junctions, defined by scanning probe lithography and geometric oxidation.'Coulomb diamond' charge stability plots are measured at 290 K, with QD addition energy ~0.3 eV. Theoretical simulation gives a QD size of similar order to the phosphorous atom separation ~2 nm. Extraction of energy states predicts an anharmonic QD potential, fitted using a Morse oscillator-like potential. The results extend single-atom transistor operation to RT, enable tunnelling spectroscopy of impurity atoms in insulators, and allow the energy landscape for P atoms in SiO2 to be determined.