Alpha particle irradiation of bulk and exfoliated MoS2 and WS2 membranes
Alpha particle irradiation of bulk and exfoliated MoS2 and WS2 membranes
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DOI：
10.1016/j.nimb.2018.01.018
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发表时间：
2018-11-15
影响因子：
1.3
通讯作者：
Baidak, Aliaksandr
中科院分区：
文献类型：
--
作者：
Isherwood, Liam H.;Worsley, Robyn E.;Baidak, Aliaksandr
二维过渡金属硫属化物（TMDC）纳米片的性质近年来得到了深入研究，因为这些化合物已成为未来电子、光子和传感器应用的有前途的材料。这些应用中的一些可能需要将纳米片暴露于辐射场，因此，了解它们与电离辐射的相互作用机制是必需的。在我们的实验中，我们管理1.66兆电子伏的氦核散装和液相剥离的二硫化钼和WS 2膜两个总吸收剂量。拉曼光谱显示在所有样品中在光谱仪分辨率内的小变化。虽然很小，但观察到一些可再现的变化，例如在高总吸收剂量辐照的块状MoS 2膜中E-2g（l）和A（lg）模式的蓝移;这些位移伴随着两个峰的小加宽。在体WS 2膜中，He 2+辐照引起2LA（M）声子模的蓝移和单调的平均峰宽减小，随着注量的增加。与这些峰位移相关的结构变化目前尚不清楚。拉曼光谱，与能量色散X-射线光谱一致，表明无定形碳存在于剥离的二硫化钼和WS 2膜照射后。有人建议，这种无定形碳可以通过残留溶剂的辐射分解非晶化形成，保留在剥离的nanosheets.Due的液相剥离的nanosheets. Due的形态，它们表现出更大的辐射稳定性比散装TMDC当暴露于重带电粒子辐射。这些结果不同于以前报道的单层和散装二硫化钼机械剥离。预期液相剥离的纳米片的相对辐射稳定性是由残留溶剂和随后产生的无定形碳对离子束能量的衰减和耗散引起的。
The properties of two-dimensional transition metal dichalcogenide (TMDC) nanosheets have been intensively studied in recent years as these compounds have emerged as promising materials for future electronic, photonic and sensor applications. Some of these applications may require the nanosheets to be exposed to radiation fields; therefore, an understanding of their interaction mechanisms with ionising radiation is required.In our experiment, we administer 1.66 MeV helium nuclei to bulk and liquid phase exfoliated MoS2 and WS2 membranes to two total absorbed doses. Raman spectroscopy shows small changes, within the spectrometer resolution, in all samples. Although small, some reproducible changes are observed such as a blueshift of the E-2g(l) and A(lg) modes in the bulk MoS2 membrane irradiated to a high total absorbed dose; these shifts are accompanied by a small broadening of both peaks. In bulk WS2 membranes, He2+ irradiation induces a blueshift and monotonic mean peak width decrease of the 2LA(M) phonon mode with increasing fluence. The structural changes associated to these peak shifts are currently unknown. Raman spectroscopy, in agreement with energy dispersive x-ray spectroscopy, shows that amorphous carbon is present in the exfoliated MoS2 and WS2 membranes after irradiation. It is suggested that this amorphous carbon could be formed by radiolytic amorphisation of residual solvent, retained within the ripplocations of the exfoliated nanosheets.Due to the morphology of the liquid phase exfoliated nanosheets, they exhibit greater radiation stability than bulk TMDCs when exposed to heavy charged particle radiation. These results differ from those previously reported for monolayer and bulk MoS2 produced by mechanical exfoliation. The relative radiation stability of the liquid phase exfoliated nanosheets is expected to arise from attenuation and dissipation of the ion beam energy by the residual solvent and the amorphous carbon subsequently produced.