Have you ever wondered what is going on electrically at the nanoscale?  Do you have a need to understand the impedance across a nanotube?  The good news - now you can find out.   Agilent engineers and scientists have now married together a network analyzer and an atomic force microscope, making it possible to make impedance and capacitance measurements at the tip of an AFM.  In fact, you can scan across a surface making these measurements. 

I remember visiting a number of research facilities shortly after Agilent announced its line of AFM’s and the big question from the researchers - “When will Agilent be able to make electrical measurements at the nanoscale?”  They were asking for worldclass measurements on objects that weren’t even visible through an optical microscope.  In effect - that day has arrived.   A whole new world of research is now available to us. 

To read more, visit the Agilent nanotechnology website and click on the image in the center of the page. 

Just about the time you think you know every instrument that exists - someone comes up with a new idea.  University of Maryland researchers have come up with something they refer to as a dielectric microwave microscope.  The combination of a microwave source and a AFM probe allows one to send microwave signals to dielectric material and look at the signals that are reflected back to the probe. 

Is this really a microscope?  According to the dictionary - a microscope is an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye.  So in the true sense, this isn’t a microscope because there are no optics and lenses.  However, it does allow one to “view” phenomena that is too small for the naked eye.  And I use the term “view” pretty loosely - a chance to better understand and/or characterize an object (or in this case, dielectric material). 

From my perspective I think we’re going to see a lot more combinations of traditional instruments to characterize / view new types of materials.  I applaud researchers who have found ways to combine different sources and sensors in order to better explain the properties and structures of nano materials.  If you would like to share your combination instruments or solicit ideas on combinational instruments - write back to this blog or send me an email (grant_drenkow@agilent.com). 

We would love to start a dialog on this subject that might lead to better measurements which in turn leads to breakthrough research and hopefully to products to improve our world.  Pretty lofty thoughts - but what you can’t measure … you can’t improve. 

To visit examples of unique measurements in the nano world - check out these application examples.   http://nano.tm.agilent.com/index.cgi?CONTENT_ID=1361&User:LANGUAGE=en-US

Isn’t it amazing how much you’ve learned over a lifetime?  Did you ever stop to think how much you’ve forgotton?   The human memory is amazing but certainly not fool-proof.  And yet even a whiff of a certain smell or a glimpse of a certain shape can bring back the memories of something in your past.

Electronic memory is also quite amazing, powering digital cameras and MP3 players.  As nanotechnology takes hold the density of the memory will continue to increase, giving us the power to capture and store nearly everything around us.  As the size shrinks, one challenge will be the testing of memory.  When dealing with nanoscale elements on a memory chip it is critical that the electronic signals be very precise. 

Fudan University in China uses a function generator to send very precise nanosecond pulses to its nanoscale memory devices.   Read more about the application in the Application Example section of the Agilent in Nanotechnology website.  http://nano.tm.agilent.com/index.cgi?CONTENT_ID=1238&User:LANGUAGE=en-US

Chemical sensing will very likely become an important field in the world of nanotechnology.  Chemical sensing plays in important role in our homes as we use carbon dioxide sensors to detect that harmful gas.  Sensors in public arenas are important to warn us of impending danger from toxic spills or terrorist attacks.  Chemical sensors in hospitals and clinics help us prevent disease or warn us of harmful viruses.  Nanotechnology will no doubt improve the sensitivity of chemical sensors making them even more useful for characterizing minute amounts of toxins or finding very early signs of disease.

Carnegie Melon University is building a chemical sensor array using inkjet printing technology.  The printed circuit board is powered with a DC power supply during the testing. To learn more about this chemical sensor - go to Application Examples on the Agilent in Nanotechnology website.

Today, Agilent begins an applications section of the nanotechnology website.  The new section is a reference of nanotechnology applications showing typical instruments being used in research projects.   Each example gives a brief description of the project, the instruments used, the measurements made, and the device or structure being studied.  It also cites the name of the article, the publication, and the authors if you want to read more about this specific application.  It is divided into chemical, electronics, life sciences, materials, and optical categories for easier reference. 

To see the applications section, go to www.agilent.com/find/nano and click on the Application Examples found on the left side navigation bar under Resources.

 Let me highlight a few of the applications available this week.  If you are interested in carbon nanotubes, check out the chemical section to see how a gas chromatograph is used as a nanotube filter.  For those in electronics, this week’s applications include optical amplifiers tested with an oscilloscope and transistors tested with a semiconductor parameter analyzer.  In life science, genes are being identified with a bioanlyzer.  In in the optical section quantum dots being used as infared photodectors are tested using a semiconductor analyzer to accurately plot their current/voltage (I-V) characteristics.  In the nanomaterials section polymer micelles are characterized with a liquid chromatograph / mass spectrometer.  An LCR meter is used to plot the capacitance/voltage (C-V) curves. 

The applications section will have weekly additions, so visit it frequently.   My thanks to Jeff Harvey, a student at the University of Colorado-Boulder, who help us put together these research summaries.  If you have an application that you would like us to highlight- reply to this blog. 

The Nobel Prize for 2007 goes to Albert Fert and Peter Grunberg for giant magnetoresistance (GMR).  The technology allows one to read very small magnetic differences stored on computer hard drives and convert it to electric current.  It enables hard drive manufacturers to store large amounts of data in a small space.  GMR is a great example of nanoscale measurements enabling breakthroughs in future commercial products. 

 Go to http://nobelprize.org/nobel_prizes/physics/laureates/2007/press.html to read the full report.

I recently attended the SPIE Optics East Conference in Boston. Nanotechnology is having a strong influence on optics. In particular, researchers are looking for a way to increase the efficiency of photovoltaics and solar cells to reduce our dependency on fossil fuel. The National Renewable Energy Laboratory (NREL) in Golden, Colorado recently hosted the Colorado Nanotechnology Alliance. An odd combination? Not really. NREL, a government-funded center, is actively testing a variety of nanotechnology materials, looking for the most efficient way to turn solar energy into electricity. An article just released talks about NREL’s interest in quantum dots to improve the efficiency of photovoltaic material. <Learn More>

Researchers like those at the University of Toronto in Canada have been looking at quantum dots for a number of years. Steven McDonald and his team have been using a semiconductor parameter analyzer to measure the low level voltage and current generated by quantum dots. In an article published in Nature Materials in January 19, 2005 they were measuring currents on the order of 100 nanoamps and voltages of around 5 volts. Semiconductor analyzers like the Agilent B1500A are ideal tools for solar panel and photovoltaic research because of their ability to measure currents down to atto-amps and voltages in the microvolts. Atomic force microscopes are nice complements to the electronic measurements, allowing one to look at the surface of material and the individual quantum dots.

For more information on Agilent’s complete line of nanotechnology - visit the nanotechnology website at www.agilent.com/find/nano

Agilent B1500A Semiconductor Analyzer

A recent bridge collapse in Minneapolis, Minnesota has prompted renewed interest in the materials science of critical infrastructures like bridges.  Bridges in the northern regions of the country have been weakened by prolonged exposure to deicing salt that finds its way through the concrete to the steel reinforcing beams causing extensive corrosion.  Cathodic protection, a technique developed in the USA and UK during the second half of the 20th century, is a possible means to protect these bridges.  Who would have thought that electronics could play a role in materials science?   If you would like to read more about this technique, visit the Agilent application note library and download this application note.  http://cp.literature.agilent.com/litweb/pdf/5989-6459EN.pdf

As I talk with university professors doing nanotechnology research, many of them are utilizing electronic test equipment in their research on various nanotechnology structures.  Semiconductor analyzers capable of low level voltage and current measurements are at the top of the list.  Network analyzers with the ability to add stimulus and measure responses in the GHz arena are also popular.  And others are using high precision multimeters, high speed oscilloscopes, RF signal generators, MHz function generators, and high precision power supplies. 

What instruments are you using in your research?  Over the course of the next few weeks I will be highlighting applications that I’ve seen using various types of electronic, chemical analysis, bioanalysis, and microscopy products for nanotechnology research.  Feel free to add your own applications to this blog. 

In the June issue of Nature Nanotechnology Harvard University and the University of Hawaii at Manoa have found a way to align carbon nanotubes and nanowires in a cm samples.  Their technique involves suspending the nanodevices in a polymer epoxy and blowing bubbles into the solution to align the nanoscale devices.   The process could lead to a way to produce arrays of transistors. 

 The researchers used an Agilent Semiconductor Analyzer to characterize the current and voltage of these aligned nanotubes and nanowires.  We know that researchers like to use these semiconductor analyzers for nanotaechnology research so we’ve added specific carbon nanotube FET set-ups in the library of functions for the Agilent B1500A Semiconductor Analyzer.  We’ve had a number of positive remarks from researchers who find the touch-screen set-up quite easy to use and flexible to implement. 

What do you use for your electrical characterizations of nanotubes and nanowires?  Post your successes so others can learn from experience. 

If you are characterizing the the electrical properties of nanoscale devices, check out a new type of instrument called the DC power analyzer.  It’s more than just a bench power supply.  I haven’t used one but those that have tell me you can quickly set it up to output sequences of voltages or currents.  It has a built-in voltmeter and digitizer that can monitor the output voltage and current from each channel, store this data, and display a graph of voltage and current versus time on the color display. 

 Why should you care?  If you are really trying to understand how much power your device draws you can now see this with one instrument.  If you want to do more than just output a simple voltage or current, you have that flexibility as well.  And if you need to vary the voltage and/or current you can do that without writing a program.  It even documents all the readings. 

What doesn’t it do?  It will never replace a high performance multimeter because the power analyzer monitors voltage and current into the device - not out of the device.  You need a multimeter for that. 

It also doesn’t replace a semiconductor or impedance analyzer.  A semiconductor analyzer is a source / measure unit but it provides much higher precision than a power analyzer.  And the power analyzer isn’t going to give you the precision of an impedance analyzer either. 

The power analyzer is a new concept but its based on proven technologies.  Let me know if you have some additional thoughts.  I think it might be a good choice the next time you are looking for a flexible power supply.

To see more information - go to http://www.home.agilent.com/agilent/redirector.jspx?action=ref&cname=PRODUCT&ckey=1123271&cc=US&lc=eng