How quickly are electrons transferred?
FAU researchers demonstrate charge transfer at attosecond scale in a Schottky junction
A team of researchers at the Department of Physics has developed a method which can be used to reliably measure the speed of electron transfer between two materials. This could lead to the development of innovative electronic components with ultrafast transfer rates. The results were published in the specialist journal Nature Photonics under the title ‘Attosecond-fast internal photoemission’.
The transfer of charges between two materials is a fundamental process in electronic components, for example in transistors or solar cells. New combinations of layered two-dimensional materials can accelerate this process enormously. Researchers led by Prof. Dr. Peter Hommelhoff from the Chair of Laser Physics in collaboration with the Chair of Applied Physics (Prof. Dr. Heiko B. Weber) have succeeded in measuring the speed of charge transfer in such heterostructures for the first time: they combined graphene, a two-dimensional layer of carbon atoms, with a semi-conductor of silicon carbide to create a Schottky junction. They then bombarded this with laser pulses and recorded how many electrons flowed out of the graphene in a particular time before photoabsorption in the material was saturated.
The scientists were able to use this method, which they named CHAMELEON, to record the fastest charge transfer ever measured between two materials: the electron transfer took just under 300 attoseconds. By way of comparison: one attosecond is one billionth of one billionth of a second. Being able to determine the exact time taken for charge transfer between various material interfaces could accelerate the development of ultrafast optoelectronic components.