Wear-resistant AFM tip; Confocal Images of larger volumes; Nanowire structure and behaviour
Wear-resistant AFM Tip
Scientists from the University of Pennsylvania, the University of Wisconsin-Madison and IBM Research-Zurich have developed an ultrasharp tip that wears away at the rate of less than one atom per millimeter of sliding on a substrate of silicon dioxide. This wear-resistant tip will be useful for thermomechanical nanofabrication using AFM probes. For this application, the tip should ideally have a high hardness, temperature stability, chemical inertness, and high thermal conductivity.
The wear rate of new tip is much lower than that of conventional silicon tips, and its hardness is 100 times greater than that of the previously state-of-the-art silicon oxide-doped diamond-like carbon tips developed by the same collaboration last year. The increased wear rate will make nanomanufacturing both practical and affordable, according to the researchers. Consisting primarily of carbon and silicon, the tip is sharpened to a nano-sized apex and integrated on the end of a silicon microcantilever. Read more about how the process developed by the scientists to create the tips in an Advanced Functional Materials paper.
Confocal images of larger volumes
University of Strathclyde researchers are creating a lens that will extend confocal microscopy to cover larger volumes, so that every cell in a piece of tissue or even an entire mouse embryo 6 mm long can be recorded in three dimensions with subcellular detail.Called the Mesolens, it will be allow scientists to capture microscopic detail of organisms that are too big to be examined with today’s confocal microscopes and will offer a deeper insight into areas such as cancerous tissues and the cortex of the brain. It will also speed up imaging by avoiding the need to stitch together images.
Dr. Brad Amos, a Visiting Scientist at the Strathclyde Institute of Pharmacy and Biomedical Sciences, discussed the device at the prestigious Leewenhoek Lecture at the Royal Society in London. Watch a video of the lecture at: http://royalsociety.org/events/2012/optical-microscope.
Nanowire structure and behaviour
Researchers at the Department of Energy's Oak Ridge National Laboratory have used multiple-probe scanning tunneling microscopy to correlate the atomic structure of nanowires with their electronic behavior.The researchers found that if they introduced defects the size of a single atom into a gadolinium silicide nanowire, it would turn into an insulator because the defect interrupted the path of electrons. Gadolinium silicide nanowires are gold promise for use in nanoelectronic devices because they are compatible with silicon technology. The researchers observed different behavior in bundles of nanowires constructed of two or more wires. In the bundles, interwire coupling stabilized the structure and led to better conductance. The work is published in a Nano Letters paper.
A one-dimensional quantum nanowire (seen in yellow on left) can turn from a conductor to an insulator with the addition of a single atomic defect, according to microscopic analysis from Oak Ridge National Laboratory. Bundles of nanowires (right) are generally more stable, leading to better conductance.
Image credit: An-Ping Li and Shengyong Qin/ORNL.
Coffee break moment
Take a microscope everywhere you go with an accessory that turns the camera on your phone into a high-resolution microscope. VTT Technical Research Centre of Finland has developed a magnetic microscope module that is accurate to one hundredth of a millimeter. The first models will be released in March.
