فهرست مطالب

Optoelectronical Nanostructures - Volume:7 Issue: 1, Winter 2022

Journal of Optoelectronical Nanostructures
Volume:7 Issue: 1, Winter 2022

  • تاریخ انتشار: 1401/01/24
  • تعداد عناوین: 6
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  • Fatemeh Rahimi, Tooraj Ghaffary *, Yaghoob Naimi, Hadi Khajehazad Pages 1-18
    In this work, the effect of magnetic field onelectronic spectra and absorption coefficient of 𝐺𝑎𝐴𝑠/𝐺𝑎1−𝑥 𝐴𝑙𝑥𝐴𝑠 spherical quantum dot (QD) and𝐺𝑎1−𝑥 𝐴𝑙𝑥𝐴𝑠/𝐺𝑎𝐴𝑠 spherical quantum anti-dot (QAD)with hydrogenic impurity are reported both theoreticallyand numerically. The theoretical results which areobtained based on perturbation theory are in agreementwith numerical results, which are obtained by using thefinite difference method. Using numerical solutions,energy eigenvalues and eigenfunctions of the Schrödingerequation in these structures are obtained. The effects ofthe magnetic field on1s→2p0 absorption coefficient andalso on 1s and 2p energy levels of the QD and the QADhave been investigated. The wave functions and energiesof an electron in these spherical systems, have beenstudied. The results clearly show that the energy levelschanges and absorption coefficients in the QD and QADmodels are significantly different. It is also observedsome new degeneracies are appeared in the QAD modelunder the applied magnetic field.
    Keywords: Confinement potential, Degeneracy, Absorption Coefficient, Energy states
  • Mahdi Mohammadkhani Ghiasvand, Zahra Ahangari *, Hamed Nematian Pages 19-36
    In this paper, we demonstrate an electrostatically dopedjunctionless tunnel field effect transistor which iscomposed of a staggered band alignment at theheterojunction. The proposed structure reduces thetunneling barrier width to have a higher on-sate currentusing Ge/GaAs heterojunction at the source-channelinterface. Due to the employment of electrostaticallydoped strategy for creating p+-n+ tunneling junction, theintroduced device has low temperature simple fabricationprocess. The device has on-state current of 1.5×10-4(A/μm), subthreshold swing of 5.15 mV/dec and on/offcurrent ratio of 1.56×1010, manifesting the design of afast switching device. In addition, statistical analysis isconducted to investigate the sensitivity of deviceperformance with respect to the variation of criticaldesign parameters. The results demonstrate that gateworkfunction and polarity gate bias are fundamentaldesign parameters and optimum value should bedetermined for them to assess efficient deviceperformance.
    Keywords: Tunnel field effect transistor, Junctionless transistor, Gate workfunction, Tunneling, Sensitivity
  • Somaye Jalaei, Javad Karamdel *, Hassan Ghalami Bavil Olyaee Pages 37-54
    Black phosphorus has been considered as oneof the most capable two-dimensional materials for use inoptoelectronic nanodevices due to its intrinsic layerednature structure, high mobility of carrier, and tunablebandgap. But its low light absorption prevents its use inhigh-efficiency photodetectors. In this study, the circularAu/Pd antenna-assisted black phosphorus mid-infraredphotodetector which significantly improves the detectionperformance in comparison with BP photodetectorswithout antenna has been proposed. By integrating acircular Au/Pd antenna on the BP surface, the light-BPinteraction was significantly increased. The simulationresults demonstrate that metallic antenna structuresimprove both light absorption and photocarrier collectionin BP phosphorus detectors. The numerical result showsthat the photocurrent of the mid-infrared antenna-assistedBP detector was 5 times larger than that of BPphotodetector without antennas.
    Keywords: Black phosphorus, two-dimensional materials, photodetectors, Bandgap, antenna, medium wavelength
  • Soroush Karimi Khorrami, Masoud Berahman *, Mojtaba Sadeghi Pages 55-66
    Recently, the semiconducting electronicproperties of different compounds of two-dimensional(2D) materials have been explored. One of the mostimportant members of this family (ZrSe2; Zirconiumdiselenide) is used to substitute the silicon in Nanoelectronics because of its considerable bandgap.Moreover, this material seems to have potentialapplication in sensing some toxic gases. In this research,we have investigated the adsorption ability of ZrSe2nanosheet structure when the CO and CO2 gas moleculesare applied to the nanosheet surface. The simulationresults show appropriate and considerable sensingproperty of this structure in presence of CO gas moleculewith stable configuration and prominent changes inamount of current after gas adsorption. The CO gasmolecule shows a stable and considerable adsorption onthe ZrSe2 structure which indicates that the ZrSe2nanosheet structure is a proper case for gas sensingapplications. I-V calculations illustrate a selectivesensitivity to this especial gas molecule.
    Keywords: transition metal dichalcogenides, ZrSe2 nanosheet, CO gas molecule, Density functional theory
  • Samira Bahrami *, Omid Bahrami Pages 67-96

    In this study, an effective numerical method wasused to describe NLO impacts on photonic crystal structures,particularly 2D TMDCs and three-dimensional (3D)materials (air and SiO2). Moreover, the amplification of thesecond harmonic (SH) efficiency in one-dimensional (1D)photonic crystals, including TMDCs, was investigated. Thesephotonic crystal structures comprise of air, SiO2, and TMDClayers that are periodically arranged; however, the first twolayers have the same thickness. The transfer matrix methodwas applied to calculate the SH efficiency and no-reductionfield approximation. The incident wavelength λ of 810 nmwas achieved by adjusting the thickness of the air and SiO2layers. In addition, by choosing a specific thickness, theharmonic waves generated in the structure interactedconstructively. The conditions were such that both thefundamental and the SH waves lay in the edge of the bandgap, where the density of electromagnetic modes andinteraction time increased. However, density ofelectromagnetic modes and interaction time interactionenhanced the efficiency of the SH efficiency.

    Keywords: Transition metal dichalcogenide, SH generation, transfer matrix method
  • Bahman Elyasi, Sahel Javahernia * Pages 97-106
    An all optical multiplexer will be implemented.Two nonlinear ring resonators with different switchingthresholds will be utilized for creating the proposedmultiplexer. The proposed structure will have two inputand one output port. A control port will be utilized todecide which input data can be illustrated at the outputport. The rise time for the proposed structure is about 2ps. The proposed device can be utilized for implementingall optical systems and networks.
    Keywords: Photonic Crystal, Ring Resonator, multiplexer, Kerr Effect