Browsing by Subject "Cutoff wavelengths"
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Item Open Access Effect of the passivation layer on the noise characteristics of mid-wave-infrared InAs / GaSb superlattice photodiodes(IEEE, 2012) Tansel, T.; Kutluer, K.; Salihoglu, Ö.; Aydınlı, Atilla; Aslan, B.; Arikan, B.; Kilinc, M. C.; Ergun, Y.; Serincan, U.; Turan, R.The authors describe the noise characterization of a mid-wavelength- infrared (MWIR) photodiode based on indium arsenide and gallium antimonide (InAs/GaSb) superlattice (SL), addressing the influence of different passivation layers applied to the surface of the device. The MWIR InAs/GaSb SL design structure is based on p-i-n configuration grown by the molecular beam epitaxy on a (001) n-GaSb substrate. The SiO 2-passivated SL photodiodes demonstrated a Schottky-limited noise up to a bias voltage of -0.1 V where the measured peak responsivity is 1.37 A/W with a cut-off wavelength of 4.9 μm and the specific detectivity as high as 1.23 × 10 12 cm. Hz 1/2 W , demonstrating the high quality of the fabricated MWIR SL photodiodes. The noise measurements exhibited a frequency-dependent plateau (i.e., 1/f noise) for unpassivated and Si 3N 4-passivated samples, whereas 1/f-type noise suppression (i.e., frequency-independent plateau) with a noise current reduction at about 30 Hz of more than one order of magnitude was observed for the SiO 2-passivated ones.Item Open Access Electronic and optical properties of 4.2 μm"N" structured superlattice MWIR photodetectors(Elsevier, 2013) Salihoglu, O.; Hostut M.; Tansel, T.; Kutluer, K.; Kilic A.; Alyoruk, M.; Sevik, C.; Turan, R.; Ergun, Y.; Aydınlı, AtillaWe report on the development of a new structure for type II superlattice photodiodes that we call the "N" design. In this new design, we insert an electron barrier between InAs and GaSb in the growth direction. The barrier pushes the electron and hole wavefunctions towards the layer edges and under bias, increases the overlap integral by about 25% leading to higher detectivity. InAs/AlSb/GaSb superlattices were studied with density functional theory. Both AlAs and InSb interfaces were taken into account by calculating the heavy hole-light hole (HH-LH) splittings. Experiments were carried out on single pixel photodiodes by measuring electrical and optical performance. With cut-off wavelength of 4.2 μm at 120 K, temperature dependent dark current and detectivity measurements show that the dark current is 2.5 × 10 -9 A under zero bias with corresponding R0A resistance of 1.5 × 104 Ω cm2 for the 500 × 500 μm2 single pixel square photodetectors. Photodetector reaches BLIP condition at 125 K with the BLIP detectivity (DBLIP) of 2.6 × 10 10 Jones under 300 K background and -0.3 V bias voltage. © 2012 Elsevier B.V. All rights reserved.Item Open Access High quantum efficiency Type-II superlattice N-structure photodetectors with thin intrinsic layers(SPIE, 2013) Ergun, Y.; Hostut, M.; Tansel, T.; Muti, bdullah; Kilic, A.; Turan, R.; Aydınlı, AtillaWe report on the development of InAs/AlSb/GaSb based N-structure superlattice pin photodiode. In this new design, AlSb layer in between InAs and GaSb layers acts as an electron barrier that pushes electron and hole wave functions towards the GaSb/InAs interface to perform strong overlap under reverse bias. Experimental results show that, with only 20 periods of intrinsic layers, dark current density and dynamic resistance at -50 mV bias are measured as 6×10-3 A/cm2 and 148 ωcm2 at 77K, respectively. Under zero bias, high spectral response of 1.2A/W is obtained at 5 μm with 50% cut-off wavelengths (λc) of 6 μm. With this new design, devices with only 146 nm thick i-regions exhibit a quantum efficiency of 42% at 3 μm with front-side illimunation and no anti-reflection coatings. © 2013 SPIE.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 Solar-blind AlGaN-based Schottky photodiodes with low noise and high detectivity(American Institute of Physics, 2002) Bıyıklı, Necmi; Aytur, O.; Kimukin, I.; Tut, T.; Özbay, EkmelWe report on the design, fabrication, and characterization of solar-blind Schottky photodiodes with low noise and high detectivity. The devices were fabricated on n-/n+ AlGaN/GaN heterostructures using a microwave compatible fabrication process. True solar-blind operation with a cutoff wavelength of ∼274nm was achieved with AlxGa1-xN (x=0.38) absorption layer. The solar-blind detectors exhibited <1.8nA/cm2 dark current density in the 0-25 V reverse bias regime, and a maximum quantum efficiency of 42% around 267 nm. The photovoltaic detectivity of the devices were in excess of 2.6×1012cmHz1/2/W, and the detector noise was 1/f limited with a noise power density less than 3×10-29A2/Hz at 10 kHz. © 2002 American Institute of Physics.