Browsing by Subject "Band gap energy"

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    High efficiency monolithic photodetectors for integrated optoelectronics in the near infrared
    (IEEE, 2009) Okyay, Ali Kemal; Onbaşlı, M. Cengiz; Ercan, Burcu; Yu H.-Y.; Ren, S.; Miller, D.A.B.; Saraswat, K.C.; Nayfeh, A.M.
    Monolithic Germanium photodetectors integrated on Si with external efficiency up to 68% at 1550nm and low dark current density 3.2mA/cm2 are demonstrated. The absorption edge red shifted by 47nm corresponding to bandgap energy reduced by 24meV. © 2009 IEEE.
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    ItemOpen Access
    Influence of coumarin as an additive on CuO nanostructures prepared by successive ionic layer adsorption and reaction (SILAR) method
    (Elsevier, 2013) Bayansal, F.; Şahin, B.; Yüksel, M.; Bıyıklı, Necmi; Çetinkara, H. A.; Güder, H. S.
    The effect of coumarin doping during the growth of CuO nanostructures by SILAR method has been studied. It was found that coumarin considerably influences the growth process, manipulates the bandgap and modifies the crystallite size of the films. XRD experiments evidenced that with higher coumarin concentrations in the growth solution, the microstrain and dislocation density increased, while the crystallite size of the films decreased. SEM images revealed that the thicknesses of the plate-like nanostructures decreased with increasing coumarin concentration. By UV/vis spectrophotometer analysis it is found that the coumarin concentration affects both the optical band gap and the transmission rate: both the band gap and spectral transmittance values of the films decreased for higher coumarin content. © 2013 Elsevier B.V. All rights reserved.
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    Theoretical investigation of InAs/GaSb type-II pin superlattice infrared detector in the mid wavelength infrared range
    (2013) Kaya, U.; Hostut, M.; Kilic, A.; Sakiroglu, S.; Sokmen I.; Ergun, Y.; Aydınlı, Atilla
    In this study, we present the theoretical investigation of type-II InAs/GaSb superlattice p-i-n detector. Kronig-Penney and envelope function approximation is used to calculate band gap energy and superlattice minibands. Variational method is also used to calculate exciton binding energies. Our results show that carriers overlap increases at GaSb/InAs interface on the higher energy side while it decreases at InAs/GaSb interface on the lower energy side with increasing reverse bias due to shifting the hole wavefunction toward to the GaSb/InAs interface decisively. Binding energies increase with increasing electric field due to overall overlap of electron and hole wave functions at the both interfaces in contrast with type I superlattices. This predicts that optical absorption is enhanced with increasing electric field. © 2013 American Institute of Physics.