A biosensor structure based on a ternary photonic crystal (TPC) containing a defect is designed and simulated. This proposed biosensor detects the concentration of glucose in human urine. Based on the transfer matrix method, we theoretically studied the transmission spectra through the TPC presuming blood samples with different refractive indices (RIs) infiltrated into the defect layer of the proposed structures. By varying the concentration of glucose in the urine, the RI of the urine is changed, which in turn changes the sensor's output response; both transmission response and resonance wavelength are affected. We evaluated average sensitivity (S) for the number of periods at different values N for optimization purposes. Our results show that the biosensor has performance parameters for a period value N ¼ 6. Indeed, a value of 1033 nm of full width at half maximum photonic bandgap can be observed with a S of 965 nm∕RIU. The quality factor is 1892.542 and the figure of merit is 756.86 RIU −1 . The proposed biosensor can be a miniaturized structure with extreme sensitivity in the concentration of glucose detection models © 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)

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Semiconducting single-wall carbon nanotubes (SWCNTs) have already emerged as a promising candidate for molecular electronics and photovoltaic applications including solar cells. Any application of semiconducting SWCNTs is primarily related to proper information about its bandgap. In this work, the impact of the chirality indices and diameters of a series of armchair and zigzag SWCNTs on the electronic properties (band gap, electronic band structure and density of states (DOS)) are investigated using semi-empirical π orbitals tight-binding (TB) method. The results indicate that the electronic behaviour of the nanotubes changes according to chirality, the total number of electronic sub-bands gets increased when the chirality increases and Van Hove singularities (VHs) appear in its electronic DOS. We have found that for small diameter tubes (less than 0.8 nm), the calculated band gaps don’t agree with DFT calculations based on ab-initio (LDA and GGA) methods, which shows that the semi-empirical TB method including π orbitals only is not sufficient to give a reasonable description of small nanotubes. All Obtained results are in good agreement with previous studies. Semiconducting SWCNTs used in this study are particularly well-suited for the nanoelectronic devices and optoelectronic applications with their direct bandgap and optical transitions, while metallic SWCNTs are considered to be ideal candidates for variety of future nanoelectronic applications such as nanocircuit interconnects and power transmission cables.

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