Navigation Links
Conducting energy on a nano scale
Date:7/15/2011

Tel Aviv Modern electronics as we know them, from televisions to computers, depend on conducting materials that can control electronic properties. As technology shrinks down to pocket sized communications devices and microchips that can fit on the head of a pin, nano-sized conducting materials are in big demand.

Now, Prof. Eran Rabani of Tel Aviv University's School of Chemistry at the Raymond and Beverly Sackler Faculty of Exact Sciences, in collaboration with Profs. Uri Banin and Oded Millo at the Hebrew University, has been able to demonstrate how semiconductor nanocrystals can be doped in order to change their electronic properties and be used as conductors. This opens a world of possibilities, says Prof. Rabani, in terms of applications of small electronic and electro-optical devices, such as diodes and photodiodes, electric components used in cellular phones, digital cameras, and solar panels.

Solar panels are typically made from a pn junction. When they absorb light, the junction separates the negatively charged electrons and the positively charged holes, producing an electrical current, explains Prof. Rabani. "With this new method for doping nanocrystals to make them both p and n type, we hope that solar panels can be made not only more efficient, but cheaper as well," he says. This research has been published recently in the journal Science.

Crystal-clear progress

According to Prof. Rabani, the quest to electrically dope nanocrystals has been an uphill battle. The crystals themselves have the capacity to self-purify, which means that they cleanse themselves of dopants. Also, he adds, some of the synthetic methods for doping were problematic on the nano-scale the crystals were unable to withstand doping techniques applicable to bulk semiconductors.

The key, explains Prof. Rabani, was to find a method for doping the nanocrystals without "bleaching" their optical properties and therefore nullifying their absorption capabilities. If you can dope nanocrystals in this way, he says, it opens the door to many practical applications based on nanocrystalline materials. "Whatever you can do with nanocrystals, you can do with doped nanocrystals and more by controlling their electronic properties."

These challenges were circumvented with the use of room temperature diffusion controlled reactions. The crystals were bathed in a solution that included the dopants, where slow diffusion allowed for impurities to find their way into the nanocrystal.

The researchers used a scanning tunneling microscope (STM), a device that images surfaces at an atomic level, in order to determine the success of their doping procedure. These measurements indicated how the Fermi energy of the nanocrystals changed upon doping, a key feature in controlling the electronic properties of electronic devices. The results, notes Prof. Rabani, indicate that the nanocrystals have been doped with both n-type dopants, indicating the presence of excess electrons in the nanocrystals, and p-type, which contribute positively charged holes to the semiconductors. This will allow for their use in electronics that require a pn junction, such as solar panels, light emitting diodes, and more.

Broadening the nanocrystal spectrum

Not only did Prof. Rabani and his fellow researchers succeed in doping nanocrystals without bleaching their optical properties, but they also were able to control the optical properties, namely, the color range that the nanocrystals produce. Once doped, the nanocrystal particles could change in color, becoming more red or blue. Prof. Rabani and his colleagues were able to develop a theory to explain these observations.

Prof. Rabani says that this technology can go a long way. Doping semiconductors, he explains, has been essential for the development of technology. "Parallel to this, we also know we want to make electrical components very small. A big portion of future electronics or optics is going to be based on doping nanoparticles."


'/>"/>

Contact: George Hunka
ghunka@aftau.org
212-742-9070
American Friends of Tel Aviv University
Source:Eurekalert

Related biology technology :

1. Scientists engineer superconducting thin films
2. PAREXEL Expert to Address Key Aspects of Conducting Clinical Trials in China at 7th Annual Partnerships in Clinical Trials Congress
3. Semiconducting nanotubes produced in quantity at Duke
4. Waukesha Electric partners with SuperPower and UH to build fault current limiting superconducting transformer for Dept. of Energy
5. MIT scientists transform polyethylene into a heat-conducting material
6. Conducting ferroelectrics may be key to new electronic memory
7. Flexible nanoantenna arrays capture abundant solar energy
8. China Bio Energy Holdings Group Reports Second Quarter 2008 Financial Results
9. GEECF: Spectrum Launches Zero Waste Philippines and Gears Towards Cheap Green Energy
10. Scientists grow nanonets able to snare added energy transfer
11. Understanding the science of solar-based energy: more researchers are better than one
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/24/2017)... ... May 24, 2017 , ... ... as treasurer for the Mid-Atlantic chapter of the Healthcare Businesswomen’s Association ... , The HBA Mid-Atlantic chapter board meets in person once each quarter and ...
(Date:5/24/2017)... (PRWEB) , ... May 24, 2017 , ... ... systems are increasingly being developed with Wi-Fi connectivity to reduce the amount of ... room to room. In addition, compact mobile devices including infusion pumps, heart and ...
(Date:5/23/2017)... ... May 23, 2017 , ... ... source of human cardiovascular cells for research and the development of cardiac ... possible to generate large numbers of cardiomyocytes (hPSC-CMs). Due to varying differentiation ...
(Date:5/23/2017)... ... , ... Vortex Biosciences , provider of circulating tumor cell (CTC) capture ... using Vortex microfluidic technology ” in Nature Precision Oncology on May 8th. The ... and Dr. Matthew Rettig at the University of California, Los Angeles. The publication describes ...
Breaking Biology Technology:
(Date:5/16/2017)... 2017  Veratad Technologies, LLC ( www.veratad.com ), an ... identity verification solutions, announced today they will participate as ... 15 thru May 17, 2017, in Washington ... Center. Identity impacts the lives of ... quickly evolving digital world, defining identity is critical to ...
(Date:4/19/2017)... York , April 19, 2017 ... as its vendor landscape is marked by the presence ... market is however held by five major players - ... Together these companies accounted for nearly 61% of the ... the leading companies in the global military biometrics market ...
(Date:4/13/2017)... 2017 According to a new market research report ... Identity Administration, and Authorization), Service, Authentication Type, Deployment Mode, Vertical, and Region ... expected to grow from USD 14.30 Billion in 2017 to USD 31.75 ... ... MarketsandMarkets Logo ...
Breaking Biology News(10 mins):