| Experimentally investigated the important properties of a graph |
|
|
|
The results of experiments and equipment used for research, scientists have published in the journal Science (Observing the Quantization of Zero Mass Carriers in Graphene)
The value of count is determined by the highest values of the mobility of charge carriers (at room temperature, it is ahead of silicon on the rate of more than a hundred times). Explanation of such characteristics of physics seen in the fact that electrons and holes in grafene have zero effective mass (in other words, their speed is not related to energy) and the «act», like photons.  NIST-built STM “shuttle” module contains the atomic-scale position-and-scan system. Graphene sample and probe tip are in the center opening. Shuttle moves between a room-temperature vacuum environment for loading to an ultracold environment for measuring. Model in background shows graphene’s honeycomb structure. With that same property to associate the other new material. We know that when a conductor in a magnetic field of the electrons start to make circular movements (pretsessirovat). Movement of the circle - periodic process, which can be viewed as a quantum oscillator and the quantum energy of the oscillator may take only a discrete number of values. These values - for conventional wire - equidistant in grafene same distance between the energy levels are different.
The authors of the work carried out direct observation of electron states in the material placed in a strong magnetic field. The experiment was carried out using a special low-temperature scanning tunneling microscope sverhvysokovakuumnogo, processed the collected data, the scientists have received the full energy spectrum of electrons field. Researchers also conducted an analysis of - another curious properties of the graph, resulting in a sharp decline in conductivity under certain conditions  The module, specifically designed for this study. The module concluded and a sample and measuring needle Curiously, the measurement of the graph grown layers, and then heated in a substrate of silicon carbide, showed that all layers behave quite independently from the others, as single, isolated two-dimensional sheets. Based on the results, researchers made the assumption that the segments of the graph is not connected to other layers in the stack, as have different rotational orientation. These findings may be useful in developing methods for the manufacture of large piles of homogeneous space for new electronic devices. Source: http://www.nist.gov/public_affairs/techbeat/tbx20090514_graphene.htm |
|
| Last Updated ( Sunday, 17 May 2009 ) |
Using innovative techniques and modern equipment group of researchers from the Georgia Institute of Technology (Georgia Institute of Technology) and the National Institute of Standards and Technology (NIST), United States conducted a direct measurement of the energy spectrum of charge carriers in grafene - so promising two-dimensional form of carbon, the properties that intrigue researchers now already 5 years old.
| < Prev | Next > |
|---|
