Carbon nanotubes may play a crucial role while developing optoelectronic components. As of now no electronic methods were probably turned fruitful to analyze the ultra fast optoelectronic dynamics of the nanotubes. A team of physicists has now laid hands on a novel method to directly measure the dynamics of photo-excited electrons in nanoscale photodetectors.
It is believed that carbon nanotubes contain a multitude of unusual properties which empowers them to play a key role in building optoelectronic components. During the research, scientists seemingly developed a measurement method allowing a time-based resolution of the so-called photocurrent in photodetectors with picosecond precision. The unique measurement technique appears around a hundred times faster than traditional methods. In the carbon nanotubes the electrons seemingly cover a distance of around 8 ten-thousandths of a millimeter or 800 nanometers in one picosecond.
“A picosecond is a very small time interval,” commented Alexander Holleitner. “If electrons traveled at the speed of light, they would make it almost all the way to the moon in one second. In a picosecond they would only cover about a third of a millimeter.”
The speed of the electrons was measured by a time-resolved laser spectroscopy process which is termed as the pump-probe technique. This technique supposedly excites electrons in the carbon nanotube by a laser pulse and analyzing the dynamics of the process through a second laser. The research findings may offer insights and analytic opportunities to a whole range of applications, including nanoscale photodetectors, photo-switches and solar cells.
The research was funded by the German Research Foundation (Cluster of Excellence Nanosystems Initiative Munich, NIM) and the Center for NanoScience (CeNS) at Ludwig-Maximilians-Universitaet Muenchen.