Featured Research

from universities, journals, and other organizations

Delving Into The Nanoscopic

Date:
September 28, 2000
Source:
Weizmann Institute
Summary:
Weizmann Institute scientists have developed a significantly improved method for evaluating ultrathin films. Potential benefits include diverse microelectronic applications and a better understanding of chemical and biological systems.

Weizmann Institute scientists develop a significantly improved method for evaluating ultrathin films. Potential benefits include diverse microelectronic applications and a better understanding of chemical and biological systems

Related Articles


New York, NY--September 25, 2000 -- Ever tried determining what's inside a layered chocolate cake without slicing it? Now, how about tackling a similar task, yet on a nanometer-scale.

For decades, thinking big has frequently meant pursuing smaller and smaller goals. Take ultrathin films for instance. Often less than 10-15 nanometers in width, ultrathin films are used in diverse applications, from optoelectronics to biological sensors. (A nanometer is roughly one 100,000th the width of a human hair.)

A central requirement for performing these Lilliputian feats is accurate composition and structural analysis. Yet, "looking inside" these films, which are often multi-layered, calls for highly sensitive probes. Most available techniques do not provide the depth information essential for evaluating layered structures. Similarly, X-rays offer a spectacular glimpse into the human body; however, determining the relative depth of individual structures is highly difficult. Techniques devised to solve this problem are generally complicated and frequently damage the sample, distorting the results.

Now, Dr. Hagai Cohen of the Weizmann Institute Chemical Services and Prof. Israel Rubinstein of the Materials and Interfaces Department have developed a novel method for evaluating ultrathin films, specifically, non-conducting films on conducting substrates. Recently appearing in Nature, their study builds upon X-ray Photoelectron Spectroscopy (XPS), a common surface analysis technique.

In XPS, the sample is irradiated with X-rays, causing photoelectrons to be ejected. By measuring the photoelectrons' energy, it is possible to determine the atoms from which they originated. Researchers have routinely used an electron flood gun to neutralize the positive surface charge formed in non-conducting samples as a natural consequence of the photoelectron ejection, since the charging affects the photoelectrons' energy, distorting the measurements.

However, proving that one person's stumbling block may be another's stepping stone, Cohen and Rubinstein realized that the charging effect actually provides structural information - the magnitude of the photoelectron energy change correlates directly with the atoms' depth within the film (the deeper the atom the smaller the change). They decided to turn things around, using the electron gun to flood the sample with low energy electrons, thus negatively charging the surface and causing controlled, easily detectable changes in the energy of the ejected photoelectrons. By measuring these changes, the researchers were able to determine both the atom type and its depth within the film.

To evaluate their approach, the scientists used one of their previous research accomplishments - a highly organized ultrathin film, which they laced with marker atoms at different depths. When tested on this system, the new method provided depth information with a superior resolution of about one nanometer while causing minimal damage to the sample. It also offered a unique side-benefit, yielding information regarding the film's electrical properties.

The Weizmann innovation should prove highly beneficial in developing a wide range of microelectronic applications as well as in studying various chemical and biological systems.

###

This research was conducted together with Prof. Abraham Shanzer of the Organic Chemistry Department, Dr. Alexander Vaskevich of the Materials and Interfaces Department, and doctoral students Ilanit Doron-Mor, Anat Hatzor and Tamar van der Boom-Moav.

A color image of a controlled surface charging in XPS is posted at http://www.weizmann.ac.il (Media Information).

The Weizmann Institute of Science, in Rehovot, Israel, is one of the world's foremost centers of scientific research and graduate study. Its 2,500 scientists, students, technicians and engineers pursue basic research in the quest for knowledge and to enhance the quality of human life. New ways of fighting disease and hunger, protecting the environment, and harnessing alternative sources of energy are high priorities at Weizmann.


Story Source:

The above story is based on materials provided by Weizmann Institute. Note: Materials may be edited for content and length.


Cite This Page:

Weizmann Institute. "Delving Into The Nanoscopic." ScienceDaily. ScienceDaily, 28 September 2000. <www.sciencedaily.com/releases/2000/09/000926072113.htm>.
Weizmann Institute. (2000, September 28). Delving Into The Nanoscopic. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/2000/09/000926072113.htm
Weizmann Institute. "Delving Into The Nanoscopic." ScienceDaily. www.sciencedaily.com/releases/2000/09/000926072113.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Who Will Failed Nuclear Talks Hurt Most?

Who Will Failed Nuclear Talks Hurt Most?

Reuters - Business Video Online (Nov. 25, 2014) With no immediate prospect of sanctions relief for Iran, and no solid progress in negotiations with the West over the country's nuclear programme, Ciara Lee asks why talks have still not produced results and what a resolution would mean for both parties. Video provided by Reuters
Powered by NewsLook.com
Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Reuters - Innovations Video Online (Nov. 25, 2014) A virtual flying enthusiast converts parts of a written-off Airbus aircraft into a working flight simulator in his northern Slovenian home. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins