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World’s thinnest X-ray detector

Researchers at the ARC Centre of Excellence for Exciton Science at Monash and RMIT Universities have developed a new fabrication process to make the world’s thinnest X-ray detector. At less than 10 nanometers thick, it more than halves the previous record.

X-rays can be broadly divided into two types: ‘hard’ X-rays are the kind used by hospitals to scan the body and ‘soft’ X-rays have a lower energy and can be used to study wet proteins and living cells. Soft X-ray detection can be done in a synchrotron, but this is very expensive and access is difficult to secure. New non-synchrotron soft X-ray laser sources could provide a cheap and accessible alternative, however, they need an ultra-sensitive detector

Tin mono-sulfide (SnS) nanosheets are a promising new detector material but there are no standard SnS nanosheet fabrication methods that allow precise control over thickness and area, the two most important variables for detector sensitivity.

To overcome this challenge, a team led by Dr Nasir Mahmood at RMIT University developed a new technique that uses liquid metal as an exfoliant to precisely control the area and thickness of SnS nanosheets. A Monash University team led by Babar Shabbir and Prof. Jacek Jasieniak then used these sheets to create the ultra-sensitive detector. They demonstrated that it could efficiently detect soft X-rays even from a region of the electromagnetic spectrum that is normally difficult to image using X-rays and which is important for biological applications. The detector’s ultra-fast response time also opens up the possibility of real-time imaging of cells.

The researchers used a combination of ultra-high resolution microscopy techniques at Microscopy Australia’s linked lab at RMIT and their Monash facility the Monash Centre for Electron Microscopy, to confirm the structural integrity of the nanosheets.

B. Shabbir et al., Adv. Functional Materials 2022
DOI: 10.1002/adfm.202105038

Atomic resolution TEM image of a tin mono-sulfide nanosheet.

July 5, 2023