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 μCGyVac−1 cm−2 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 × 104 μCGyVac−1 cm−2 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.

Multienergy X‐ray detection is critical to effectively differentiate materials in a variety of diagnostic radiology and nondestructive testing applications. Silicon and selenium X‐ray detectors are the most common for multienergy detection; however, these present poor energy discrimination across the broad X‐ray spectrum and exhibit limited spatial resolution due to the high thicknesses required for radiation attenuation. Here, an X‐ray detector based on solution‐processed thin‐film metal halide perovskite that overcomes these challenges is introduced. By harnessing an optimized n‐i‐p diode configuration, operation is achieved across a broad range of soft and hard X‐ray energies stemming from 0.1 to 10's of keV. Through detailed experimental and simulation work, it is shown that optimized Cs0.1FA0.9PbI3 perovskites effectively attenuate soft and hard X‐rays, while also possessing excellent electrical properties to result in X‐ray detectors with high sensitivity factors that exceed 5 × 103 µnormalC boldnormalGyVac−1 cm−2$\mu {\rm{C}}\;{{\bf Gy}}_{{\rm{Vac}}}^{ - 1}\;{\rm{c}}{{\rm{m}}^{ - 2}}$ and 6 × 104 µC Gy−1 cm−2 within soft and hard X‐ray regimes, respectively. Harnessing the solution‐processable nature of the perovskites, roll‐to‐roll printable X‐ray detectors on flexible substrates are also demonstrated.

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We have investigated the role of pseudo-spin polarization in electron wave packet dynamics in pristine graphene and in a graphene antidot lattice subject to an external magnetic field. Employing a Green's function formalism, we show that the electron dynamics can be controlled by tuning pseudospin polarization. In Landau quantized graphene, we find that an electron wave packet propagates in the direction of initial pseudospin polarization with no splitting; Zitterbewegung oscillations are found to persist. In the case of a graphene antidot lattice, the electron wave packet propagates along the axis of the antidot lattice when the initial pseudospin is parallel to this axis. We also show that the probability of finding an electron along the axis of the antidot lattice increases with the strength of the antidot potential. This suggests that a graphene antidot lattice can serve as a channel for electron transport with the possibility of tunability by means of pseudospin polarization, antidot potential and applied normal magnetic field strength.