Adhesive Tape Helps Create Innovative THz Photodetector
It is 10,000 times thinner than a sheet of paper and has been inspired by the discovery made by Nobel Prize winners Andre Geim and Konstantin Novoselov.
An international team of researchers, including scientists at HSE University and Moscow Pedagogical State University (MPGU), has developed a novel photodetector composed of a thin superconducting film, capable of detecting weak terahertz (THz) radiation. This discovery holds promise for studying objects in space, developing wireless broadband communication systems, and making advancements in spectroscopy. The study has been published in Nano Letters.
The study was conducted with support from the Russian Science Foundation (RSF), Projects No. 21-72-10117 and No. 23-72-00014.
Superconducting Hot-Electron Bolometers are a type of highly sensitive photodetectors capable of capturing low-intensity electromagnetic radiation in the terahertz range. These detectors find application in astronomy for studying space objects such as stars, galaxies, and cosmic microwave radiation. Additionally, they are sought after in security and medical diagnostic systems, as they facilitate the visualisation of concealed objects with resolutions reaching hundreds of micrometres.
When the photosensitive element of such a detector absorbs electromagnetic radiation, it undergoes local heating, leading to the formation of thermalised electrons with kinetic energy surpassing the material's average electron energy. The emergence of overheated electrons causes a shift in the resistance of the photosensitive element, thereby generating an electrical signal that can be measured.
Current commercial superconducting bolometers employing overheated electrons are manufactured using films produced through magnetron sputtering techniques. This technology presently lacks the capability to produce materials thinner than a few nanometres, whereas the detector's performance is directly influenced by the deposition quality.
An international team of researchers, including scientists at MIEM HSE, have proposed using a thinner material and an alternative method for applying the detector’s photosensitive element. Taking inspiration from Nobel Prize winners Andre Geim and Konstantin Novoselov, who produced graphene by repeatedly cleaving graphite with adhesive tape, the study authors successfully obtained ultrathin films of niobium diselenide (NbSe2) by delaminating atomic layers from the material using polymer adhesive tape.
Research Fellow, MIEM HSE
We worked as part of a large international collaboration consisting of specialists in photodetectors and experts in two-dimensional materials. We pooled our expertise to develop a sensitive and compact terahertz radiation detector with a thickness of just a few atomic layers of niobium diselenide, which is 10,000 times thinner than a standard sheet of office paper. Furthermore, this technology enables us to obtain materials with an optimal structure. It is easy to apply and does not require specialised equipment.
The authors also investigated the reaction of NbSe2 to THz radiation. They examined how the material heats up upon exposure to an electromagnetic wave and how the detector's properties vary depending on its environment—the substrate and electrodes—given that two-dimensional materials are sensitive to their surroundings. The scientists have also identified the mechanisms that constrain the sensitivity and speed of the detector.
The scientists emphasise that their pioneering work to develop a bolometric THz radiation detector demonstrates the potential for such a device to eventually surpass existing commercial solutions.
Doctoral student and Research Fellow, MIEM HSE
We have demonstrated that using the proposed technology makes it possible to manufacture a bolometric THz radiation detector with characteristics similar to those of existing commercial counterparts.
See also:
Smartphones Not Used for Digital Learning among Russian School Students
Despite the widespread use of smartphones, teachers have not fully integrated them into the teaching and learning process, including for developing students' digital skills. Irina Dvoretskaya, Research Fellow at the HSE Institute of Education, has examined the patterns of mobile device use for learning among students in grades 9 to 11.
Working while Studying Can Increase Salary and Chances of Success
Research shows that working while studying increases the likelihood of employment after graduation by 19% and boosts salary by 14%. One in two students has worked for at least a month while studying full time. The greatest benefits come from being employed during the final years of study, when students have the opportunity to begin working in their chosen field. These findings come from a team of authors at the HSE Faculty of Economic Sciences.
Beauty in Details: HSE University and AIRI Scientists Develop a Method for High-Quality Image Editing
Researchers from theHSE AI Research Centre, AIRI, and the University of Bremen have developed a new image editing method based on deep learning—StyleFeatureEditor. This tool allows for precise reproduction of even the smallest details in an image while preserving them during the editing process. With its help, users can easily change hair colour or facial expressions without sacrificing image quality. The results of this three-party collaboration were published at the highly-cited computer vision conference CVPR 2024.
HSE Scientists Have Examined Potential Impact of Nuclear Power on Sustainable Development
Researchers at HSE University have developed a set of mathematical models to predict the impact of nuclear power on the Sustainable Development Index. If the share of nuclear power in the global energy mix increases to between 20% and 25%, the global Sustainable Development Index (SDI) is projected to grow by one-third by 2050. In scenarios where the share of nuclear power grows more slowly, the increase in the SDI is found to be lower. The study has been published in Nuclear Energy and Technology.
HSE Scientists Have Developed a New Model of Electric Double Layer
This new model accounts for a wide range of ion-electrode interactions and predicts a device's ability to store electric charge. The model's theoretical predictions align with the experimental results. Data on the behaviour of the electric double layer (EDL) can aid in the development of more efficient supercapacitors for portable electronics and electric vehicles. The study has been published in ChemPhysChem.
Psychologists from HSE University Discovered How Love for Animals Affects Relationships with People
Researchers from HSE University have identified a connection between attachment to pets and attitudes toward nature and other people. The study found that the more joy people derive from interacting with their pets, the more they want to help others. However, love for animals is not always associated with concern for nature. The findings were published in the Social Psychology and Society journal.
HSE Scientists Propose Using Heart Rate Analysis to Diagnose Anxiety and Depression
A group of scientists at HSE University have discovered how anxiety and depression can be diagnosed by analysing heart rate. It turns out that under mental stress, the heart rate of individuals with a predisposition to mental health disorders differs from that of healthy individuals, especially when performing more complex tasks. These changes in cardiovascular parameters can even be detected using a pulse oximeter or a smartwatch. The study findings have been published in Frontiers in Psychiatry.
Researchers at HSE in St Petersburg Develop Superior Machine Learning Model for Determining Text Topics
Topic models are machine learning algorithms designed to analyse large text collections based on their topics. Scientists at HSE Campus in St Petersburg compared five topic models to determine which ones performed better. Two models, including GLDAW developed by the Laboratory for Social and Cognitive Informatics at HSE Campus in St Petersburg, made the lowest number of errors. The paper has been published in PeerJ Computer Science.
Narcissistic and Workaholic Leaders Guide Young Firms to Success
Scientists at HSE University—St. Petersburg studied how the founder's personal characteristics impact a young firm's performance. It turns out that a narcissist and workaholic who also fosters innovation will effectively grow their company. The paper has been published in IEEE Transactions on Engineering Management.
Biologists at HSE University Warn of Potential Errors in MicroRNA Overexpression Method
Researchers at HSE University and the RAS Institute of Bioorganic Chemistry have discovered that a common method of studying genes, which relies on the overexpression of microRNAs, can produce inaccurate results. This method is widely used in the study of various pathologies, in particular cancers. Errors in experiments can lead to incorrect conclusions, affecting the diagnosis and treatment of the disease. The study findings have been published in BBA.