Tuesday, October 11, 2011

ITE 221 - Fall 2011 - Chapter 5

Article Review "Nonvolatile memory based on ferroelectric-graphene field-effect transistors is now a step closer to reality" by Lee Swee Heng, 24 Feb 11 at www.physorg.com/pdf217772766.pd

     Graphene is a single atom-thick layer of carbon atoms bonded in a hexagonal honeycomb-like arrangement that has unique electrical, optical, mechanical and thermal properties. As a result, its technological applications are researched across a wide range of applications. In fact, the Nobel Prize for Physics  for 2010 was awarded to Andre Geim and Konstantin Novoselov   "for groundbreaking experiments regarding the two-dimensional material graphene." One example is its potential use as a viable, high-performance replacement for silicon to provide nonvolatile memory for field effect transistors (FETs). 
        According to this article, scientists from two teams, the A*STAR Institute of Materials Research and Engineering and the National University of Singapore, led by Kui Yao and Barbaros Özylmaz,have collaborated to fabricate a device that includes an additional silicon dioxide (SiO2) dielectric gate below the graphene layer to simplify bit writing by providing an additional background source of charge carriers. This solved a previous problem by allowing the ferroelectric polarization to be switched between two stable states corresponding to two opposite polarization orientations. The team met with success  including the capability for symmetrical bit writing with a resistance ratio  of over 500% and reproducible nonvolatile switching over 100,000 cycles. These reversible switches could potentially be applied to nonvolatile memory. 

The full study can be found at http://prl.aps.org/abstract/PRL/v105/i16/e166602.
 

Saturday, October 1, 2011

ITE 221 - Fall - Blog 4 Chapter 4

Article Review "Finisar Expands WaveShaper Instrument Portfolio for Optical System Testing Applications: Introduction of C+L Band Optical Processor and Laser Channel Emulation Enables New Testing Capabilities"
Posted on http://www.marketwatch.com Sept 13, 2011


This press release discusses Finisar's new WaveShaper Programmable Optical Processor designed for system testing of reconfigurable optical networks as well as for laser pulse shaping in metrology and medical systems.  Finisar has provided optics technologies to system manufacturers to meet the increasing demands for network bandwidth and storage for over 20 years. Their new products, the WaveShaper 1000S/X and 4000S/X, offer an extended wavelength range covering both the C- and the L-band of the optical communications window in a single instrument. The increased frequency range provides benefits to multiple applications. For example, in metrology, broader bandwidth ultrafast pulses can now be accurately manipulated.