Highly Sensitive Ultrathin X-Ray Detectors

Highly Sensitive Ultrathin X-Ray Detectors

Author: ChemistryViews

X-ray-based methods are often very useful in structural characterization. X-rays can be classified as soft or hard: Hard X-rays with photon energies over 10 keV are used, e.g., in radiology or security systems, while soft X-rays with photon energies of 0.1–10 keV are used, for example, in microscopy or spectroscopy. Soft X-rays can be used in the direct probing of biological specimens in aqueous media. For such measurements, X-rays in the “water window” region of 200–600 eV are used to minimize absorption from the aqueous medium. There is a need for high-performance soft X-ray detectors.

Babar Shabbir, Jacek J. Jasieniak, Monash University, Clayton, Australia, Nasir Mahmood, Quaid-I-Azam University, Islamabad, Pakistan, and colleagues have developed a direct soft X-ray detector based on ultrathin tin sulfide (SnS) nanosheets. The team used a liquid-metal based exfoliation method to obtain high-quality, large-area nanosheets. First, molten tin droplets were sulfurized, and then a Si/SiO2 substrate was brought into contact with a sulfurized liquid metal droplet to allow the exfoliation of SnS nanosheets.

The researchers built X-ray detectors (pictured) by depositing gold electrodes directly onto exfoliated SnS nanosheets on Si/SiO2 substrates. The photocurrent under soft X-rays was then measured. The team found that the devices can efficiently detect soft X-ray photons within the water window with high sensitivity and low response times. The properties of the developed system compare favorably with existing direct soft X-ray detectors.



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