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:10/11/2017)... and LAGUNA HILLS, Calif. , Oct. ... Cancer Research, London (ICR) and University ... SKY92, SkylineDx,s prognostic tool to risk-stratify patients with multiple myeloma ... MUK nine . The University of Leeds ... partly funded by Myeloma UK, and ICR will perform the ...
(Date:10/10/2017)... ... 2017 , ... San Diego-based team building and cooking events company, Lajollacooks4u, has ... The bold new look is part of a transformation to increase awareness, appeal to ... period. , It will also expand its service offering from its signature gourmet cooking ...
(Date:10/10/2017)... 10, 2017 International research firm Parks Associates announced ... at the TMA 2017 Annual Meeting , October 11 in ... residential home security market and how smart safety and security products impact ... Parks Associates: Smart Home ... "The residential security market has ...
(Date:10/9/2017)... DIEGO , Oct. 9, 2017  BioTech ... biological mechanism by which its ProCell stem cell ... critical limb ischemia.  The Company, demonstrated that treatment ... amount of limbs saved as compared to standard ... the molecule HGF resulted in reduction of therapeutic ...
Breaking Biology Technology:
(Date:3/28/2017)... , March 28, 2017 The ... Hardware (Camera, Monitors, Servers, Storage Devices), Software (Video Analytics, ... Region - Global Forecast to 2022", published by MarketsandMarkets, ... 2016 and is projected to reach USD 75.64 Billion ... and 2022. The base year considered for the study ...
(Date:3/24/2017)... 24, 2017 The Controller General of Immigration from ... Abdulla Algeen have received the prestigious international IAIR Award for the ... Continue Reading ... ... Controller Abdulla Algeen (small picture on the right) have received the IAIR ...
(Date:3/23/2017)... The report "Gesture Recognition and Touchless Sensing Market by Technology (Touch-based ... to 2022", published by MarketsandMarkets, the market is expected to be worth USD ... 2022. Continue Reading ... ... ...
Breaking Biology News(10 mins):