Thanks to nanoscale devices that are comparable in size to human cells, scientists are making tremendous advancements in material properties, resulting in electronics that are smaller, quicker, and more energy-efficient. Nonetheless, to fully harness the capabilities of nanotechnology, managing noise remains essential. A research team from Chalmers University of Technology in Sweden has made noteworthy progress in understanding the fundamental limits of noise, which could greatly benefit future nanoelectronics.
Thanks to nanoscale devices comparable in size to human cells, scientists can achieve remarkable material properties, resulting in electronics that are more compact, faster, and more energy-efficient. Nevertheless, to unlock the full potential of nanotechnology, managing noise is essential. A team of researchers from Chalmers University of Technology in Sweden has made significant advancements in understanding fundamental noise constraints, paving the way for future developments in nanoelectronics.
Nanotechnology is advancing at a rapid pace, gaining interest from various sectors such as communication and energy production. At the nanoscale—which measures just a millionth of a millimeter—particles operate according to quantum mechanical principles. By leveraging these properties, materials can be engineered to achieve higher levels of conductivity, magnetism, and energy efficiency.
“Today, we are witnessing the real-life effects of nanotechnology; nanoscale devices contribute to faster technologies, and nanostructures enhance the efficiency of materials for energy production,” states Janine Splettstösser, a Professor of Applied Quantum Physics at Chalmers.
Devices smaller than human cells unlocking innovative electronic and thermoelectric traits
To control electrical charge and energy flows at the single-electron level, researchers utilize nanoscale devices, which are even smaller than human cells. These nanoelectronic systems can act as “tiny engines,” performing specific functions by harnessing quantum mechanical traits.
“At the nanoscale, devices can exhibit completely new and desirable features. These devices, which can be from a hundred to ten thousand times smaller than a human cell, enable the design of highly efficient energy conversion processes,” explains Ludovico Tesser, a PhD candidate in Applied Quantum Physics at Chalmers University of Technology.
Tackling nano-noise: a vital challenge
Despite advancements, noise remains a major barrier in the progression of nanotechnology research. This disruptive noise is generated by fluctuations in electrical charge and thermal effects within devices, which impedes their precise and reliable performance. Although considerable efforts have been made, scientists still struggle to determine how much of this noise can be eliminated without compromising energy conversion, and our understanding of its underlying mechanisms is still limited. Fortunately, the research group at Chalmers has achieved an important breakthrough.
In a recent study, published as an editor’s suggestion in Physical Review Letters, the team explored nanoscale thermoelectric heat engines. These specialized devices are engineered to manage and convert waste heat into electrical energy.
“All electronic devices generate heat, and recently, significant efforts have gone into understanding how this heat can be converted to usable energy at the nano level. Tiny thermoelectric heat engines utilize quantum mechanical properties and nonthermal effects and, much like miniature power plants, can convert heat into electrical energy instead of letting it dissipate,” notes Professor Splettstösser.
Finding the balance between noise and energy in nanoscale heat engines
However, nanoscale thermoelectric heat engines perform more efficiently when subjected to substantial temperature gradients. These temperature differences add complexity to the already challenging task of studying and understanding noise. Fortunately, the Chalmers researchers have illuminated a crucial relationship between noise levels and power output in thermoelectric heat engines.
“We can demonstrate that there is a fundamental limit to noise that directly influences the performance of the ‘engine.’ For instance, we have observed that if we want the device to produce a considerable amount of power, we must accept higher noise levels, as well as quantifying the specific amount of noise. This reveals a trade-off: how much noise must be tolerated to extract a certain amount of power from these nanoscale engines. We hope these insights will guide future designs of nanoscale thermoelectric devices with greater precision,” says Ludovico Tesser.