New electron microscope pushes nanoscale materials up

Dutch scientists have succeeded in improving the imaging resolution of an electron microscope by a factor 2.5, by using a new type of detector. Their success is going to push efficiency and sensitivity on nanoscale materials research: it will actually make it possible to design and build the thinnest materials with improved control and quality. These processes are significant for the development of micro- and nano-electronics.

The tests with the new detector were performed by scientists from the Dutch Universities of Leiden and Twente, and IBM.This research is the first phase of the Escher Project (University of Leiden) which is supported by a 2.3 million Euro government grant through the Dutch Organization for Scientific Research (NOW).

The improvement of imaging resolution allows the Low Energy Electron Microscope (LEEM) to be used for experiments on the growth and properties of the thinnest materials on the planet, which consist of only a single atomic layer of carbon, known as graphene. This material is considered very promising for novel electronic applications. LEEM was developed to observe graphene growth processes on surfaces on the nanometer scale in real-time.

“Low Energy Electron Microscopy, a relative newcomer in the field of microscopy, is steadily gaining importance in both industrial and academic research. It is the leading technique in studies of processes that are essential for the development of micro- and nano-electronics”, says Ruud Tromp of IBM´s T.J Watson Research Center and professor at Leiden University: “In a conventional electron microscope, the electrons are accelerated to high energies to irradiate the sample. What is special about LEEM is that it uses low energy electrons. Such slow electrons are very sensitive to the finest structures at the surface. Magnetic electron lenses use the reflected electrons to form a video image of the sample and even of its electronic properties. A better detector of course results in a better image.”

The improvement in imaging resolution has been made possible by a high tech CMOS detector, called Medipix2. Medipix2 was originally developed by CERN, the Dutch NIKHEF organization, and others, to detect X-rays. Instead, Leiden University researchers Sense Jan van der Molen, Irakli Sikharulidze and Ruud Tromp of IBM installed a Medipix2 detector in the  LEEM instrument at the University of Twente. Given the excellent results, the researchers expect that Medipix2 will be standard in future LEEM instruments.

The advantages of the improved image quality are significant for the development of micro- and nanotechnology. For instance, it will now be possible to study the growth and properties of graphene in depth, thereby opening up new opportunities, including developing smaller and smarter storage and memory devices.

Graphene opens up new possibilities for electronics and spintronics, but the important step from laboratory to industry has not yet been made. With LEEM, the growth of graphene can be imaged live, enabling the development of large-scale manufacturing methods. It is also a big step forwards for studies of exotic combinations between metals and organic molecular materials, as explored in molecular electronics. Plans for Escher include a series of experiments with molecular layers that are exactly one molecule thick (‘self-assembled monolayers’). By careful choice of the molecules, we can give a surface new properties, for example in controlling how well water wets the surface, which may be important in biological applications.

The Escher microscope will be installed at Leiden University later this year. Originally designed by Ruud Tromp, the instrument will be further developed by Leiden University. Escher will cover a temperature range from almost absolute zero to above 1500 Celsius. Many materials are fabricated at high temperatures, but the properties of interest occur only at very low temperatures. Escher will now be able to study high temperature fabrication processes and low temperature properties in a single instrument.


1 Comment

  1. Electron microscopic techniques achieve a scale of resolution limited by the electron’s wavelength, giving an array of images with remarkable value for study of biological or material examples. The advancements to smaller scales of pico and femtometric imaging will have the vital importance of defining atomic structure and electron topology. That will lead to the quantum age of data-intensive IT and progressive innovation.
    Femtoscale imaging will display electrons in detail, a necessary step before nanoelectronics can begin chip design with methodical, scientific efficiency.
    When the scale advances to view single atoms the images will be out ahead of the state-of-the-art of physics, though. There is no distinct atomic wavefunction, giving it topological definition, beyond the Schrodinger wavefunction based on nonrelativistic, statistical estimative principles.
    That may be improved by RQT physics by building an atomic topological wavefunction which is a combination of the relativistic Einstein-Lorenz transform functions for time, mass, and energy with the workon quantized electromagnetic wave equations for frequency and wavelength. This model depicts the atom, labeled psi (Z), as a nucleus radiating forcons with valid joule values by relativistic {e=m(c^2)} transform of it’s nucleoplastic surface layer to force fields. The equation models these events as a series differential with quantum symmetry numbers assigned along the progression of orders to give topology to the solutions.
    Psi pulsates by cycles of nuclear emission and absorption of force at the frequency {Nhu=e/h}, within spacetime limits of {gravity-time}, to compose the GT integral atomic wavefunction.
    Next, when the atom’s internal momentum function is rearranged to the photon gain rule and integrated for GT boundaries, a series of 26 wavefunctions is found. Each is the topological definition function for a type of energy intermedon of the psi’s 5/2 kT J internal heat capacity energy cloud, accounting for all of them, and their values intersect those of the fundamental physical constants: h, h-bar, delta, nuclear magneton, beta magneton, k (series). Each of those is displayed as a picoyoctometric 3D image.
    The result is the 3D interactive video atomic model image, responsive to keyboard entry simulated photon gain events by quantized shifts of internal, and surface, force and energy fields. The GT integral builds an accurate, picoyoctometric virtual atom.
    Views of the h-bar magnetic energy waveparticle of ~175 picoyoctometers are available at with the complete guide to RQT atomic modeling titled The Crystalon Door. TCD conforms to the unopposed motion of disclosure in U.S. District (NM) Court titled The Solution to the Equation of Schrodinger, U.S. copyright TXu1-266-788.

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