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Theoretical characterization of strain and interfacial electronic effects in donor-acceptor bilayers of 2D transition metal dichalcogenides
摘要： Amine Slassi1, Jér?me Cornil1,* E-mail : jerome.cornil@umons.ac.be Bilayers of 2D Transition Metal Dichalcogenides 1Laboratory for Chemistry of Novel Materials, University of Mons, BE-7000 Mons, Belgium Theoretical Characterization of Strain and Interfacial Electronic Effects in Donor-Acceptor Two-dimensional (2D) materials and their van der Waals (vdW) stacked hetero-structures are promising candidates for highly efficient (opto)-electronic applications. The performance of vdW these properties are affected when building a bilayer. We focus on MoS2-based bilayers, including MoS2/MoS2, WS2/MoS2, MoSe2/MoS2 and WSe2/MoS2 structures. The impact of properties of two-dimensional transition metal dichalcogenide (TMDs) monolayers and the way vacancies on the interlayer interactions is also investigated. The main finding of our calculations first?principle calculations, we have explored systematically the structural and electronic is that changes in the properties of 2D monolayers upon building stack do occur and are driven by heterostructures in devices strongly depend on electronic processes at their interfaces. Here, using both strain effects and interfacial electronic processes.
关键词： defect vacancy,first-principles calculations,vdW heterostructures,electronic processes,strain effects
更新于2025-09-23 15:21:01
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Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature
摘要： We present the results of an experimental study about strain effects on the core band gap and diameter of spherical bare CdSe core and CdSe/ZnS core/shell quantum dots (QDs) synthesized by using a colloidal technique at varying temperatures. Structural characterizations were made by using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) techniques. Optical characterizations were made by using UV-Vis absorption and fluorescence emission spectroscopies. The XRD analysis suggests that the synthesized bare CdSe core and CdSe/ZnS core/shell QDs have zinc blende crystal structure. HRTEM results indicate that the CdSe core and CdSe/ZnS QDs have average particle sizes about 3.50 nm and 4.84 nm, respectively. Furthermore, compressive strain causes an increase (decrease) in the core band gap (diameter) of spherical CdSe/ZnS core/shell QDs at any temperature. An elastic strain-modified effective mass approximation (EMA) predicts that there is a parabolic decrease (increase) in the core band gap (diameter) of QDs with temperature. The diameter of spherical bare CdSe core and CdSe/ZnS core/shell QDs calculated by using the strain-modified EMA, with core band gap extracted from absorption spectra, are in excellent agreement with the HRTEM data.
关键词： diameter,quantum dots,band gap,CdSe,strain effects,CdSe/ZnS,temperature
更新于2025-09-12 10:27:22