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Lattice thermal conduction in suspended molybdenum disulfide monolayers with defects
摘要： In this study, we investigated the effect of lattice defects comprising vacancies and boundaries on the lattice thermal conductivity (LTC), k p, of suspended molybdenum disulfide monolayers (MLs) over a wide temperature range (1 < T < 500 K). By using the phonon Boltzmann formalism, the acoustic phonons were considered to be scattered by the sample and grain boundaries, isotopic impurities, vacancies, and other phonons via Umklapp and normal (N-) processes. k p was evaluated using a modified Callaway model by considering the in-plane longitudinal acoustic and transverse acoustic phonons, and out-of-plane flexural acoustic phonon modes. We demonstrated the need to include the often neglected non-resistive N-processes when evaluating the LTC. Numerical calculations of the temperature dependence of the LTC for crystalline and polycrystalline MoS2 MLs showed the dominance of sample-dependent scattering mechanisms at low temperatures (T < 100 K) and of phonon-phonon scattering at higher temperatures, where the N-processes played an important role. The effects of vacancies and boundaries were to alter the behavior and suppress the magnitude of the LTC. The suppression due to vacancies was greater in crystalline MLs with specular surfaces and in polycrystalline MLs with larger grain sizes. The calculations compared well with recent thermal conductivity data obtained for polycrystalline samples. The need for further investigations is suggested.
关键词： MoS2 monolayer,grain boundary scattering,vacancy scattering,lattice thermal conductivity,N-process
更新于2025-09-23 15:23:52
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Pd-doped MoS2 monolayer: A promising candidate for DGA in transformer oil based on DFT method
摘要： Density functional theory (DFT) method was carried out to simulate the adsorption of three dissolved gases on Pd-doped MOS2 (Pd-MoS2) monolayer. We initially studied the possible structures of Pd-MoS2 monolayer and found that the Pd dopant preferred to be adsorbed onto the surface by TMo site. The adsorption and desorption performance, along with the sensing principle of Pd-MoS2 towards three typical gases, including H2, CH4 and C2H2, were analyzed. These analysis indicated that Pd-MoS2 could be a satis?ed material for C2H2 and H2 sensing at speci?c condition; while it is unsuitable for detection of CH4 due to the weak interaction and extremely short recovery time. All these give a ?rst insight into the application of Pd-MoS2 for DGA, evaluating the working operation of the transformer through sensitive detection of H2 and C2H2. We are hopeful that this work would support informative knowledge for experimentalists to realize the potential of Pd-MoS2 in the ?eld of electrical engineering in the near future.
关键词： DGA,Transformer oil,DFT,Pd-MoS2 monolayer
更新于2025-09-10 09:29:36