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:
Similar Comprehension, Different Reading: How Native Language Affects Reading in English as a Second Language
Researchers from the MECO international project, including experts from the HSE Centre for Language and Brain, have developed a tool for analysing data on English text reading by native speakers of more than 19 languages. In a large-scale experiment involving over 1,200 people, researchers recorded participants’ eye movements as they silently read the same English texts and then assessed their level of comprehension. The results showed that even when comprehension levels were the same, the reading process—such as gaze fixations, rereading, and word skipping—varied depending on the reader's native language and their English proficiency. The study has been published in Studies in Second Language Acquisition.
Mortgage and Demography: HSE Scientists Reveal How Mortgage Debt Shapes Family Priorities
Having a mortgage increases the likelihood that a Russian family will plan to have a child within the next three years by 39 percentage points. This is the conclusion of a study by Prof. Elena Vakulenko and doctoral student Rufina Evgrafova from the HSE Faculty of Economic Sciences. The authors emphasise that this effect is most pronounced among women, people under 36, and those without children. The study findings have been published in Voprosy Ekonomiki.
Scientists Discover How Correlated Disorder Boosts Superconductivity
Superconductivity is a unique state of matter in which electric current flows without any energy loss. In materials with defects, it typically emerges at very low temperatures and develops in several stages. An international team of scientists, including physicists from HSE MIEM, has demonstrated that when defects within a material are arranged in a specific pattern rather than randomly, superconductivity can occur at a higher temperature and extend throughout the entire material. This discovery could help develop superconductors that operate without the need for extreme cooling. The study has been published in Physical Review B.
Scientists Develop New Method to Detect Motor Disorders Using 3D Objects
Researchers at HSE University have developed a new methodological approach to studying motor planning and execution. By using 3D-printed objects and an infrared tracking system, they demonstrated that the brain initiates the planning process even before movement begins. This approach may eventually aid in the assessment and treatment of patients with neurodegenerative diseases such as Parkinson’s. The paper has been published in Frontiers in Human Neuroscience.
Civic Identity Helps Russians Maintain Mental Health During Sanctions
Researchers at HSE University have found that identifying with one’s country can support psychological coping during difficult times, particularly when individuals reframe the situation or draw on spiritual and cultural values. Reframing in particular can help alleviate symptoms of depression. The study has been published in Journal of Community Psychology.
Scientists Clarify How the Brain Memorises and Recalls Information
An international team, including scientists from HSE University, has demonstrated for the first time that the anterior and posterior portions of the human hippocampus have distinct roles in associative memory. Using stereo-EEG recordings, the researchers found that the rostral (anterior) portion of the human hippocampus is activated during encoding and object recognition, while the caudal (posterior) portion is involved in associative recall, restoring connections between the object and its context. These findings contribute to our understanding of the structure of human memory and may inform clinical practice. A paper with the study findings has been published in Frontiers in Human Neuroscience.
Researchers Examine Student Care Culture in Small Russian Universities
Researchers from the HSE Institute of Education conducted a sociological study at four small, non-selective universities and revealed, based on 135 interviews, the dual nature of student care at such institutions: a combination of genuine support with continuous supervision, reminiscent of parental care. This study offers the first in-depth look at how formal and informal student care practices are intertwined in the post-Soviet educational context. The study has been published in the British Journal of Sociology of Education.
AI Can Predict Student Academic Performance Based on Social Media Subscriptions
A team of Russian researchers, including scientists from HSE University, used AI to analyse 4,500 students’ subscriptions to VK social media communities. The study found that algorithms can accurately identify both high-performing students and those struggling with their studies. The paper has been published in IEEE Access.
HSE Scientists: Social Cues in News Interfaces Build Online Trust
Researchers from the HSE Laboratory for Cognitive Psychology of Digital Interface Users have discovered how social cues in the design of news websites—such as reader comments, the number of reposts, or the author’s name—can help build user trust. An experiment with 137 volunteers showed that such interface elements make a website appear more trustworthy and persuasive to users, with the strongest cue being links to the media’s social networks. The study's findings have been published in Human-Computer Interaction.
Immune System Error: How Antibodies in Multiple Sclerosis Mistake Their Targets
Researchers at HSE University and the Institute of Bioorganic Chemistry of the Russian Academy of Sciences (IBCh RAS) have studied how the immune system functions in multiple sclerosis (MS), a disease in which the body's own antibodies attack its nerve fibres. By comparing blood samples from MS patients and healthy individuals, scientists have discovered that the immune system in MS patients can mistake viral proteins for those of nerve cells. Several key proteins have also been identified that could serve as new biomarkers for the disease and aid in its diagnosis. The study has been published in Frontiers in Immunology. The research was conducted with support from the Russian Science Foundation.