Nanowires (NWs) have witnessed tremendous development over the past two decades owing to their varying potential applications. Semiconductor NWs often contain stacking faults due to the presence of coexisting phases, which frequently hampers their use. Herein, it is investigated how stacking faults affect the optical properties of bent ZnSe and CdSe NWs, which are synthesized using the vapor transport method. Polytypic zinc blende-wurtzite structures are produced for both these NWs by altering the growth conditions. The NWs are bent by the mechanical buckling of poly(dimethylsilioxane), and micro-photoluminescence (PL) spectra were then collected for individual NWs with various bending strains (0-2%). The PL measurements show peak broadening and red shifts of the near-band-edge emission as the bending strain increases, indicating that the bandgap decreases with increasing the bending strain. Remarkably, the bandgap decrease is more significant for the polytypic NWs than for the single phase NWs. This work provides insights into flexible electronic devices of 1D nanostructures by engineering the polytypic structures.
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http://dx.doi.org/10.1002/smll.201603695 | DOI Listing |
Materials (Basel)
January 2025
Nanoscience and Nanoengineering Programme, İstanbul Technical University, Maslak Campus, İstanbul 34469, Turkey.
We propose a temperature-dependent optimization procedure for the second-nearest neighbor (2NN) * tight-binding (TB) theory parameters to calculate the effects of strain, structure dimensions, and alloy composition on the band structure of heterostructure spherical core/shell quantum dots (QDs). We integrate the thermoelastic theory of solids with the 2NN * TB theory to calculate the strain, core and shell dimensions, and composition effects on the band structure of binary/ternary CdSe/Cd(Zn)S and ZnSe/Zn(Cd)S QDs at any temperature. We show that the 2NN * TB theory with optimized parameters greatly improves the prediction of the energy dispersion curve at and in the vicinity of L and X symmetry points.
View Article and Find Full Text PDFSmall
January 2025
Engineering Research Center in Biomaterials, Sichuan University, Chengdu, Sichuan, 610065, P. R. China.
InP-based quantum dots (QDs) are widely adopted as a superior alternative to CdSe-based QDs in various fields owing to their high quantum yield, environmental friendliness, and excellent stability. However, improving its color purity remains a challenging task. In this work, we employ a multistage heating strategy to optimize the nucleation and shell growth processes of amino-phosphine-based InP/ZnSe/ZnS QDs for reducing emission linewidths.
View Article and Find Full Text PDFAccurate measurement of nonlinear absorption coefficients by transmission-based techniques, such as Z-scan and its modifications, remains challenging due to high measurement errors. In this Letter, we claim that one of the reasons for that could lie in ignoring multiple reflections of light in plane-parallel samples in the presence of multi-photon excitation. Closed-form formulations for transmittance and reflectance coefficients, considering both linear and multiphoton absorption, are obtained in the geometrical optics approximation.
View Article and Find Full Text PDFPhys Chem Chem Phys
October 2024
School of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610101, China.
Recently, the search for materials with high photoelectric conversion efficiency has emerged as a significant research hotspot. Unlike p-n junctions, the bulk photovoltaic effect (BPVE) can also materialize within pure crystals. Here, we propose wurtzite and zinc blende semiconductors without inversion symmetry (AgI, GaAs, CdSe, CdTe, SiGe, ZnSe, and ZnTe) as candidates for achieving the BPVE and investigate the factors that affect the shift current.
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