English Abstract
Abstract:
The structural characteristics of biological specimens, such as wet proteins and fixed living cells, can be conveniently probed in their host aqueous media using soft X-rays in the water window region (200–600 eV). Conventional X-ray detectors in this area exhibit low spatial resolution, have limited sensitivity, and require complex fabrication procedures. Here, many of these limitations are overcome by introducing a direct soft X-ray detector based on ultrathin tin mono-sulfide (SnS) nanosheets. The distinguishing
characteristic of SnS is its high photon absorption efficiency in the soft X-ray region. This factor enables the fabricated soft X-ray detectors to exhibit excellent sensitivity values on the order of 104 µCGy c Va
− − 1 2 c m− at peak energies of ≈600 eV. The peak signal is found to be sensitive to the number of stacked SnS layers, with thicker SnS nanosheet assemblies yielding a peak response
at higher energies and with peak sensitives of over 2.5 × µ 104 CGy c Va − − 1 2 c m− at 1 V. Detailed current–voltage and temporal characteristics of these detectors are also presented. These results showcase the excellent performance of SnS nanosheet-based soft X-ray detectors compared to existing direct soft X-ray detectors, including that of the emerging organic–inorganic perovskite class of materials.
