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.
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 t
|Contact: George Hunka|
American Friends of Tel Aviv University