Browsing by Author "Muti, A."
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Item Open Access A Comparative Passivation Study for InAs / GaSb Pin Superlattice Photodetectors(IEEE Institute of Electrical and Electronics Engineers, 2013-08) Salihoglu, O.; Muti, A.; Aydınlı, AtillaIn the quest to find ever better passivation techniques for infrared photodetectors, we explore several passivation layers using atomic layer deposition (ALD). We compare the impact of these layers on detectors fabricated under same conditions. We use ALD deposited Al2O3, HfO2, TiO2, ZnO, plasma enhanced chemical vapor deposition deposited SiO2, Si3N4, and sulfur containing octadecanethiol self assembled monolayer passivation layers on InAs/GaSb p-i-n superlattice diodes with an average cutoff wavelength of 5.1 mu m. Passivated and unpassivated photodetectors compared for their electrical performances.Item Open Access N structure for type-II superlattice photodetectors(American Institute of Physics, 2012-08-14) Salihoglu, O.; Muti, A.; Kutluer, K.; Tansel, T.; Turan, R.; Ergun, Y.; Aydınlı, AtillaIn the quest to raise the operating temperature and improve the detectivity of type II superlattice (T2SL) photodetectors, we introduce a design approach that we call the "N structure." N structure aims to improve absorption by manipulating electron and hole wavefunctions that are spatially separated in T2SLs, increasing the absorption while decreasing the dark current. In order to engineer the wavefunctions, we introduce a thin AlSb layer between InAs and GaSb layers in the growth direction which also acts as a unipolar electron barrier. Unlike the symmetrical insertion of AlSb into GaSb layers, N design aims to exploit the shifting of the electron and hole wavefunctions under reverse bias. With cutoff wavelength of 4.3 mu m at 77 K, temperature dependent dark current and detectivity measurements show that the dark current density is 3.6 x 10(-9) A/cm(2), under zero bias. Photodetector reaches background limited infrared photodetection (BLIP) condition at 125 K with the BLIP detectivity (D-BLIP*) of 2.6 x 10(10) Jones under 300 K background and -0.3 V bias voltage.Item Open Access Skin-like self-assembled monolayers on InAs / GaSb superlattice photodetectors(IOP Institute of Physics Publishing, 2012) Salihoglu, O.; Muti, A.; Kutluer, K.; Tansel, T.; Turan, R.; Aydınlı, AtillaWe report on the effects of monolayer (ML) thick skin-like octadecanethiol (ODT, CH 3[CH 2] 17SH) on type-II InAs/GaSb MWIR photodetectors. Circumventing the ageing effects of conventional sulfur compounds, we use ODT, a self-assembling, long molecular chain headed with a sulfur atom. Photodiodes coated with and without the self-assembled monolayer (SAM) ODT were compared for their electrical and optical performances. For ODT-coated diodes, the dark current density was improved by two orders of magnitude at 77K under 100mV bias. The zero bias responsivity and detectivity were 1.04AW 1 and 2.15 × 10 13 Jones, respectively, at 4μm and 77K. The quantum efficiency was determined to be 37% for a cutoff wavelength of 5.1μm.Item Open Access Surface recombination noise in InAs / GaSb superlattice photodiodes(IOP Institute of Physics Publishing, 2013) Tansel, T.; Kutluer, K.; Muti, A.; Salihoglu, Ö.; Aydınlı, Atilla; Turan, R.The standard Schottky noise approach alone is not sufficient to describe the noise mechanism in an InAs/GaSb superlattice photodetector at reverse negative bias. The additional noise identified appears at surface activation energies below 60meV and is inversely proportional to the reverse bias. In order to satisfactorily explain the experimental data, we hereby propose the existence of a surface recombination noise that is a function of both the frequency and bias. The calculated noise characteristics indeed show good agreement with the experimental data.