Taking advantage of the favorable Gibbs free energies, atomic layer deposited (ALD) aluminum oxid... more Taking advantage of the favorable Gibbs free energies, atomic layer deposited (ALD) aluminum oxide (Al2O3) was used as a novel approach for passivation of type II InAs/GaSb superlattice (SL) midwave infrared (MWIR) single pixel photodetectors in a self cleaning process (λcut-off ∼ 5.1 μm). Al2O3 passivated and unpassivated diodes were compared for their electrical and optical performances. For passivated diodes, the dark current density was improved by an order of magnitude at 77 K. The zero bias responsivity and detectivity was 1.33 A/W and 1.9 × 1013 Jones, respectively at 4 μm and 77 K. Quantum efficiency (QE) was determined as %41 for these detectors. This conformal passivation technique is promising for focal plane array (FPA) applications.
The resonance behavior of localized surface plasmons in silver
and gold nanoparticles was studied... more The resonance behavior of localized surface plasmons in silver and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size, shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements. The results are compared with the theoretical calculations based on the DDA simulations performed by software developed in this study. We propose a new intensity modulation technique based on localized surface plasmons in nanoparticles with asymmetric shapes.
... distribution. On the other hand, as it is well known from the Monte Carlo calculations, the p... more ... distribution. On the other hand, as it is well known from the Monte Carlo calculations, the peak position of the defects introduced by the ion implantation process is located closer to the surface compared to the Si atom distribution [16]. ...
Abstract This work describes the application of laser ion source~ LIS! for fabrication of semicon... more Abstract This work describes the application of laser ion source~ LIS! for fabrication of semiconductor nanostructures, as well as relevant equipment completed and tested in the IPPLM for the EU STREP “SEMINANO” project and the obtained experimental results. A repetitive pulse laser system of parameters: energy of; 0.8 J in a 3.5 ns-pulse, wavelength of 1.06 mm, repetition rate of up to 10 Hz and intensity on the target of up to 1011 W0cm2, has been employed to produce Ge ions intended for ion implantation into SiO2 substrate. ...
There has been much interest in semiconductor nanocrystals embedded in oxides and their interesti... more There has been much interest in semiconductor nanocrystals embedded in oxides and their interesting optical and electrical properties, which can potentially be utilised in future devices. We have studied the effects of different processing parameters on the formation of Ge nanocrystals in SiO2 prepared by ion implantation followed by heat treatment. We implanted Ge doses of between 2×1015 and 1×1017 cm−2 at implantation energy of 30 or 100 keV and used a range of annealing temperatures and times. The samples were investigated using transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDS), secondary ion mass spectroscopy (SIMS) and Raman spectroscopy. Ge nanocrystals were observed for doses of 3×1016 and 1×1017 cm−2 at 100 keV after annealing at 800 °C. Annealing of similar samples at 1000 °C yielded no nanocrystals. We believe that diffusion of oxidising species from the atmosphere is important and that this process is faster at 1000 than at 800 °C, creating Ge-rich amorphous oxides rather than Ge nanocrystals at the higher temperature. This oxidation process also explains the absence of Ge nanocrystals in SiO2 films implanted with Ge at 30 keV after annealing. Electron beam-induced precipitation was observed in samples with amorphous Ge-rich layers under intense electron irradiation in the TEM. Accumulation of Ge at the Si/SiO2 interface was observed in samples implanted at 100 keV and annealed at 1000 °C or higher temperatures.
Electroluminescence (EL) and photoluminescence (PL) measurements were conducted on Si-implanted S... more Electroluminescence (EL) and photoluminescence (PL) measurements were conducted on Si-implanted SiO2 layers as a function of process and measurement parameters. Measurable light emission was observed from the metal oxide semiconductor light emitting diode (MOS-LED) when holes are injected from the substrate. It was shown that major PL and EL emissions have the same origin. However, two important differences were observed between EL and PL spectra. The first one is the light emission from the Si substrate due to the recombination of electrons supplied by the front contact and holes that were accumulated in the inversion region at the substrate/SiO2 interface. This might be a factor reducing the contribution of Si nanocrystals to the EL emission of the MOS-LED structure as a result of decrease in the number of holes in the inversion layer. The second difference is that EL emission peaks stay at a slightly higher energy than PL peaks. It was observed that the EL peak shifts towards the PL peak with increasing bias voltage. This behaviour is explained by considering the size distribution of nanocrystals formed by ion implantation.
Si nanocrystals in thermal oxide films (~250 nm) were fabricated by 100 keV Si ion implantation a... more Si nanocrystals in thermal oxide films (~250 nm) were fabricated by 100 keV Si ion implantation at various doses followed by high temperature annealing. After annealing a sample implanted with a dose of 1×1017 cm-2 at 1050°C for 2 h, a broad photoluminescence peak centred around 880 nm was observed. A dose of 5×1016 cm-2 yields a considerable blue shift of about 100 nm relative to the higher dose. Transmission electron microscopy and atomic force microscopy (AFM) are used to characterize the microstructures in the SiO2 film. The limitations of these techniques for the study of the nanostructures are addressed in this paper and it is suggested that AFM combined with etching can yield a structural spectroscopy with very good sensitivity.
... Page 6. 1076 O. Karabulut et al.: Properties of Si implanted GaSe single crystal ... Acknowle... more ... Page 6. 1076 O. Karabulut et al.: Properties of Si implanted GaSe single crystal ... Acknowledgements This work is partially supported by METU-AFP with project number 2001-07-02-00-13. Authers would like to thank to Dr. Ergun Tasarkuyu and Ugur Serincan for their helps. ...
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2008
... Abstract. The use of Al 2 O 3 dielectric in MOS based radiation sensors has been investigated... more ... Abstract. The use of Al 2 O 3 dielectric in MOS based radiation sensors has been investigated. ... [12] A. Jaksic, G. Ristic, M. Pejovic, A. Mohammadzadeh, C. Sudre and W. Lane, Gamma-ray irradiation and post-irradiation responses of high dose range RADFETs, IEEE Trans. Nucl. ...
Taking advantage of the favorable Gibbs free energies, atomic layer deposited (ALD) aluminum oxid... more Taking advantage of the favorable Gibbs free energies, atomic layer deposited (ALD) aluminum oxide (Al2O3) was used as a novel approach for passivation of type II InAs/GaSb superlattice (SL) midwave infrared (MWIR) single pixel photodetectors in a self cleaning process (λcut-off ∼ 5.1 μm). Al2O3 passivated and unpassivated diodes were compared for their electrical and optical performances. For passivated diodes, the dark current density was improved by an order of magnitude at 77 K. The zero bias responsivity and detectivity was 1.33 A/W and 1.9 × 1013 Jones, respectively at 4 μm and 77 K. Quantum efficiency (QE) was determined as %41 for these detectors. This conformal passivation technique is promising for focal plane array (FPA) applications.
The resonance behavior of localized surface plasmons in silver
and gold nanoparticles was studied... more The resonance behavior of localized surface plasmons in silver and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size, shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements. The results are compared with the theoretical calculations based on the DDA simulations performed by software developed in this study. We propose a new intensity modulation technique based on localized surface plasmons in nanoparticles with asymmetric shapes.
... distribution. On the other hand, as it is well known from the Monte Carlo calculations, the p... more ... distribution. On the other hand, as it is well known from the Monte Carlo calculations, the peak position of the defects introduced by the ion implantation process is located closer to the surface compared to the Si atom distribution [16]. ...
Abstract This work describes the application of laser ion source~ LIS! for fabrication of semicon... more Abstract This work describes the application of laser ion source~ LIS! for fabrication of semiconductor nanostructures, as well as relevant equipment completed and tested in the IPPLM for the EU STREP “SEMINANO” project and the obtained experimental results. A repetitive pulse laser system of parameters: energy of; 0.8 J in a 3.5 ns-pulse, wavelength of 1.06 mm, repetition rate of up to 10 Hz and intensity on the target of up to 1011 W0cm2, has been employed to produce Ge ions intended for ion implantation into SiO2 substrate. ...
There has been much interest in semiconductor nanocrystals embedded in oxides and their interesti... more There has been much interest in semiconductor nanocrystals embedded in oxides and their interesting optical and electrical properties, which can potentially be utilised in future devices. We have studied the effects of different processing parameters on the formation of Ge nanocrystals in SiO2 prepared by ion implantation followed by heat treatment. We implanted Ge doses of between 2×1015 and 1×1017 cm−2 at implantation energy of 30 or 100 keV and used a range of annealing temperatures and times. The samples were investigated using transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDS), secondary ion mass spectroscopy (SIMS) and Raman spectroscopy. Ge nanocrystals were observed for doses of 3×1016 and 1×1017 cm−2 at 100 keV after annealing at 800 °C. Annealing of similar samples at 1000 °C yielded no nanocrystals. We believe that diffusion of oxidising species from the atmosphere is important and that this process is faster at 1000 than at 800 °C, creating Ge-rich amorphous oxides rather than Ge nanocrystals at the higher temperature. This oxidation process also explains the absence of Ge nanocrystals in SiO2 films implanted with Ge at 30 keV after annealing. Electron beam-induced precipitation was observed in samples with amorphous Ge-rich layers under intense electron irradiation in the TEM. Accumulation of Ge at the Si/SiO2 interface was observed in samples implanted at 100 keV and annealed at 1000 °C or higher temperatures.
Electroluminescence (EL) and photoluminescence (PL) measurements were conducted on Si-implanted S... more Electroluminescence (EL) and photoluminescence (PL) measurements were conducted on Si-implanted SiO2 layers as a function of process and measurement parameters. Measurable light emission was observed from the metal oxide semiconductor light emitting diode (MOS-LED) when holes are injected from the substrate. It was shown that major PL and EL emissions have the same origin. However, two important differences were observed between EL and PL spectra. The first one is the light emission from the Si substrate due to the recombination of electrons supplied by the front contact and holes that were accumulated in the inversion region at the substrate/SiO2 interface. This might be a factor reducing the contribution of Si nanocrystals to the EL emission of the MOS-LED structure as a result of decrease in the number of holes in the inversion layer. The second difference is that EL emission peaks stay at a slightly higher energy than PL peaks. It was observed that the EL peak shifts towards the PL peak with increasing bias voltage. This behaviour is explained by considering the size distribution of nanocrystals formed by ion implantation.
Si nanocrystals in thermal oxide films (~250 nm) were fabricated by 100 keV Si ion implantation a... more Si nanocrystals in thermal oxide films (~250 nm) were fabricated by 100 keV Si ion implantation at various doses followed by high temperature annealing. After annealing a sample implanted with a dose of 1×1017 cm-2 at 1050°C for 2 h, a broad photoluminescence peak centred around 880 nm was observed. A dose of 5×1016 cm-2 yields a considerable blue shift of about 100 nm relative to the higher dose. Transmission electron microscopy and atomic force microscopy (AFM) are used to characterize the microstructures in the SiO2 film. The limitations of these techniques for the study of the nanostructures are addressed in this paper and it is suggested that AFM combined with etching can yield a structural spectroscopy with very good sensitivity.
... Page 6. 1076 O. Karabulut et al.: Properties of Si implanted GaSe single crystal ... Acknowle... more ... Page 6. 1076 O. Karabulut et al.: Properties of Si implanted GaSe single crystal ... Acknowledgements This work is partially supported by METU-AFP with project number 2001-07-02-00-13. Authers would like to thank to Dr. Ergun Tasarkuyu and Ugur Serincan for their helps. ...
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2008
... Abstract. The use of Al 2 O 3 dielectric in MOS based radiation sensors has been investigated... more ... Abstract. The use of Al 2 O 3 dielectric in MOS based radiation sensors has been investigated. ... [12] A. Jaksic, G. Ristic, M. Pejovic, A. Mohammadzadeh, C. Sudre and W. Lane, Gamma-ray irradiation and post-irradiation responses of high dose range RADFETs, IEEE Trans. Nucl. ...
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Papers by Rasit Turan
and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size,
shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements. The results are compared with the theoretical calculations based on the DDA simulations performed by software developed in this study. We propose a new intensity modulation technique based on localized surface plasmons in nanoparticles with asymmetric shapes.
and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size,
shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements. The results are compared with the theoretical calculations based on the DDA simulations performed by software developed in this study. We propose a new intensity modulation technique based on localized surface plasmons in nanoparticles with asymmetric shapes.