Olga Jakšić | University of Belgrade (original) (raw)
Papers by Olga Jakšić
Chemosensors, May 22, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Универзитет у Београду, Apr 29, 2014
Proceedings of SPIE, May 20, 2009
We analyzed the intrinsic noise of plasmonic sensors caused by the adsorption-desorption of gaseo... more We analyzed the intrinsic noise of plasmonic sensors caused by the adsorption-desorption of gaseous analytes on the sensor surface. We analyzed a general situation when there is a larger number of different species in the environment. We developed our model and applied it to calculate various analyte mixtures, including some environmental pollutants, toxic and dangerous substances. The spectral density of
ABSTRACT Scientists in the field of NEMS today are focused on the problem of achieving the lowest... more ABSTRACT Scientists in the field of NEMS today are focused on the problem of achieving the lowest detectable mass of the atomic force microscope and molecular microscope probes. This paper deals with this problem starting from the theory of the adsorption-desorption noise and also the noise caused by temperature fluctuations and Johnson's noise. We found that the adsorption-desorption noise clearly exceeds the noise of the other sources at lower frequencies. According to the results we obtained for a typical microcantilever fabricated by NEMS processes, the order of magnitude of the noise equivalent mass (NEM) is NEM∼104 D (1 D=1.7·10-27 kg).
Materials Research Bulletin, Feb 1, 2006
Microbial fuel cells (MFC) present bioelectrochemical systems that allow generation of electricit... more Microbial fuel cells (MFC) present bioelectrochemical systems that allow generation of electricity during anaerobic respiration of selected bacterial species. They have very promising applications in wastewater purification systems, as biosensors or as alternative power source. This work is a result of joint multidisciplinary research and presents preliminary experimental results obtained by electrical characterization of a single-chamber MFC. The goal of research was to study activity of MFC and estimate its internal resistance.
Elektronika, Jul 15, 2016
The aim of this work was to experimentally explore possibility of gas type and pressure detection... more The aim of this work was to experimentally explore possibility of gas type and pressure detection using ICTM multipurpose device based on Seebeck effect. For this purpose, experimental procedure was established which allowed testing in the pressure range (2· 102 -2·103) Pa. Thermopile voltage was measured in the atmosphere of argon, carbon dioxide and helium. Experimental results justified to some extent simulation data. It was proven that output voltage can serve both for gas type and gas pressure detection.
Lecture Notes in Electrical Engineering, 2023
Surfaces, Aug 24, 2020
Surface density of adsorption sites on an adsorbent (including affinity-based sensors) is one of ... more Surface density of adsorption sites on an adsorbent (including affinity-based sensors) is one of the basic input parameters in modeling of process kinetics in adsorption based devices. Yet, there is no simple expression suitable for fast calculations in current multiscale models. The published experimental data are often application-specific and related to the equilibrium surface density of adsorbate molecules. Based on the known density of adsorbed gas molecules and the surface coverage, both of these in equilibrium, we obtained an equation for the surface density of adsorption sites. We applied our analysis to the case of pristine graphene and thus estimated molecular dynamics of adsorption on it. The monolayer coverage was determined for various pressures and temperatures. The results are verified by comparison with literature data. The results may be applicable to modeling of the surface density of adsorption sites for gas adsorption on other homogeneous crystallographic surfaces. In addition to it, the obtained analytical expressions are suitable for training artificial neural networks determining the surface density of adsorption sites on a graphene surface based on the known binding energy, temperature, mass of adsorbate molecules and their affinity towards graphene. The latter is of interest for multiscale modelling.
Micromachines, Aug 26, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Facta universitatis - series: Electronics and Energetics
Modeling of adsorption and desorption in microelectromechanical systems (MEMS) generally is cruci... more Modeling of adsorption and desorption in microelectromechanical systems (MEMS) generally is crucial for their optimization and control, whether it is necessary to decrease the adsorption-desorption influence (thus ensuring stable operation of ultra-precise micro and nanoresonators) or to increase it (and enhancing in this manner the sensitivity of chemical and biological resonant sensors). In this work we derive and use analytical mathematical expressions to model stochastic fluctuations of the mass adsorbed on the MEMS resonator (mass loading noise). We consider the case where the resonator surface incorporates two different types of binding sites and where non-negligible depletion of the adsorbate occurs in a closed resonator chamber. We arrive at a novel expression for the power spectral density of mass loading noise in resonators and prove the necessity of its application in cases when resonators are exposed to low adsorbate concentrations. We use the novel approach presented he...
Solid State Electronics Letters, 2020
Plasmonic metamaterials open a pathway to a multitude of different applications, from ultrasensit... more Plasmonic metamaterials open a pathway to a multitude of different applications, from ultrasensitive sensors to merging the packaging density of electronics and the speed of photonics in a single all-optical device. A severe limitation to their wider use is high absorption due to the mandatory presence of free electron-containing conductive parts which are lossy by definition. In this contribution we consider an alternative solution in the form of ultrathin silicon films deposited on a silica substrate. The films are patterned as arrays of elongated rhombuses acting as bowtie nanoantennas. We consider the effect of sharp tips and the proximity effect on the electromagnetic field concentration in such low-loss metasurfaces. Our structures have the advantage of very low absorption losses with an order of magnitude field enhancement and the virtue of full compatibility with the standard planar technologies. This makes them convenient for various practical applications which integrate high field concentration with e.g. waveguiding properties, for instance microreactors, labs-on-a-chip, photocatalytic systems and various other Micro-Opto-Electro-Mechanical System (MOEMS) devices integrating optical, microfluidic and other functionalities.
2019 International Semiconductor Conference (CAS)
Plasmonic metamaterials offer a multitude of different applications. A limitation to their wider ... more Plasmonic metamaterials offer a multitude of different applications. A limitation to their wider use is high absorption. Here we consider an alternative solution in the form of silicon-silica nanocomposites to be used as metasurface-based optical concentrators with decreased losses. To this purpose we design and simulate arrays of bowtie nanoantennas, built in ultrathin silicon films on a silica substrate. In comparison to plasmonic structures, field localization is weaker. On the other hand, our structures have very low absorption losses and a full compatibility with standard planar technologies. This makes them convenient for microreactors, lab-on-a-chip devices and various microfluidic MEMS systems.
We present an analysis of noise currents in magnetoconcentration HgCdTe and InSb photodetectors w... more We present an analysis of noise currents in magnetoconcentration HgCdTe and InSb photodetectors with nonequilibrium suppression of Auger processes. These detectors are intended for the detection of infrared radiation in the (8-14) mm range at elevated temperatures and generation-recombination noise is the parameter limiting their performace. Its suppression is essential for the proper operation of these detectors. We also shortly consider 1/f (flicker) noise and the influence of magnetic field on its value.
In this paper we propose a novel operating principle for thermal vacuum sensor. The sensor consid... more In this paper we propose a novel operating principle for thermal vacuum sensor. The sensor considered in this work consists of thermopiles and thermally isolating membrane structure. The operating principle of such sensor would be based on monitoring thermal time constant dependence on pressure. In order to get the most prominent effect, sensor fabricated on SOI wafer is studied. Simulation was performed using 1D analytical model. It is shown that sensors performance could be improved by increasing the number of thermocouples. Apart from that it is demonstrated that performance of such sensor depends also on gas present in the housing so the same device could be also used as a gas type detector.
Solid State Phenomena, 1998
We performed an analysis of the absorption coefficient and refractive index in mercury cadmium te... more We performed an analysis of the absorption coefficient and refractive index in mercury cadmium telluride single crystalline layers fabricated by liquid phase and vapor phase epitaxy for a large number of samples with different compositions (0.165<x<0.3) and degrees of carrier degeneracy (n < 10^19 cm^-3). The transmission of samples was measured by LWIR (long wavelength infrared) spectrometry, and carrier concentration was determined by the Hall method. In our analysis of the measured results we used the generalized model of infrared absorption in mercury cadmium telluride, where the interband absorption was calculated using the Kane kP approach which takes into account the Urbach band tailing, the non parabolicity of bands and the Moss-Burstein bandfilling effect, and we also applied our approximate relations based on this model. In the long wavelength region, we took into account the absorption on free carriers. To calculate the values of the transmission coefficient we used a multilayer thin film approach. The connection between the real part of the refractive index and the infrared absorption coefficient was determined using the Kramers-Kronig relations and by applying empirical models.
Chemosensors, May 22, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Универзитет у Београду, Apr 29, 2014
Proceedings of SPIE, May 20, 2009
We analyzed the intrinsic noise of plasmonic sensors caused by the adsorption-desorption of gaseo... more We analyzed the intrinsic noise of plasmonic sensors caused by the adsorption-desorption of gaseous analytes on the sensor surface. We analyzed a general situation when there is a larger number of different species in the environment. We developed our model and applied it to calculate various analyte mixtures, including some environmental pollutants, toxic and dangerous substances. The spectral density of
ABSTRACT Scientists in the field of NEMS today are focused on the problem of achieving the lowest... more ABSTRACT Scientists in the field of NEMS today are focused on the problem of achieving the lowest detectable mass of the atomic force microscope and molecular microscope probes. This paper deals with this problem starting from the theory of the adsorption-desorption noise and also the noise caused by temperature fluctuations and Johnson's noise. We found that the adsorption-desorption noise clearly exceeds the noise of the other sources at lower frequencies. According to the results we obtained for a typical microcantilever fabricated by NEMS processes, the order of magnitude of the noise equivalent mass (NEM) is NEM∼104 D (1 D=1.7·10-27 kg).
Materials Research Bulletin, Feb 1, 2006
Microbial fuel cells (MFC) present bioelectrochemical systems that allow generation of electricit... more Microbial fuel cells (MFC) present bioelectrochemical systems that allow generation of electricity during anaerobic respiration of selected bacterial species. They have very promising applications in wastewater purification systems, as biosensors or as alternative power source. This work is a result of joint multidisciplinary research and presents preliminary experimental results obtained by electrical characterization of a single-chamber MFC. The goal of research was to study activity of MFC and estimate its internal resistance.
Elektronika, Jul 15, 2016
The aim of this work was to experimentally explore possibility of gas type and pressure detection... more The aim of this work was to experimentally explore possibility of gas type and pressure detection using ICTM multipurpose device based on Seebeck effect. For this purpose, experimental procedure was established which allowed testing in the pressure range (2· 102 -2·103) Pa. Thermopile voltage was measured in the atmosphere of argon, carbon dioxide and helium. Experimental results justified to some extent simulation data. It was proven that output voltage can serve both for gas type and gas pressure detection.
Lecture Notes in Electrical Engineering, 2023
Surfaces, Aug 24, 2020
Surface density of adsorption sites on an adsorbent (including affinity-based sensors) is one of ... more Surface density of adsorption sites on an adsorbent (including affinity-based sensors) is one of the basic input parameters in modeling of process kinetics in adsorption based devices. Yet, there is no simple expression suitable for fast calculations in current multiscale models. The published experimental data are often application-specific and related to the equilibrium surface density of adsorbate molecules. Based on the known density of adsorbed gas molecules and the surface coverage, both of these in equilibrium, we obtained an equation for the surface density of adsorption sites. We applied our analysis to the case of pristine graphene and thus estimated molecular dynamics of adsorption on it. The monolayer coverage was determined for various pressures and temperatures. The results are verified by comparison with literature data. The results may be applicable to modeling of the surface density of adsorption sites for gas adsorption on other homogeneous crystallographic surfaces. In addition to it, the obtained analytical expressions are suitable for training artificial neural networks determining the surface density of adsorption sites on a graphene surface based on the known binding energy, temperature, mass of adsorbate molecules and their affinity towards graphene. The latter is of interest for multiscale modelling.
Micromachines, Aug 26, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Facta universitatis - series: Electronics and Energetics
Modeling of adsorption and desorption in microelectromechanical systems (MEMS) generally is cruci... more Modeling of adsorption and desorption in microelectromechanical systems (MEMS) generally is crucial for their optimization and control, whether it is necessary to decrease the adsorption-desorption influence (thus ensuring stable operation of ultra-precise micro and nanoresonators) or to increase it (and enhancing in this manner the sensitivity of chemical and biological resonant sensors). In this work we derive and use analytical mathematical expressions to model stochastic fluctuations of the mass adsorbed on the MEMS resonator (mass loading noise). We consider the case where the resonator surface incorporates two different types of binding sites and where non-negligible depletion of the adsorbate occurs in a closed resonator chamber. We arrive at a novel expression for the power spectral density of mass loading noise in resonators and prove the necessity of its application in cases when resonators are exposed to low adsorbate concentrations. We use the novel approach presented he...
Solid State Electronics Letters, 2020
Plasmonic metamaterials open a pathway to a multitude of different applications, from ultrasensit... more Plasmonic metamaterials open a pathway to a multitude of different applications, from ultrasensitive sensors to merging the packaging density of electronics and the speed of photonics in a single all-optical device. A severe limitation to their wider use is high absorption due to the mandatory presence of free electron-containing conductive parts which are lossy by definition. In this contribution we consider an alternative solution in the form of ultrathin silicon films deposited on a silica substrate. The films are patterned as arrays of elongated rhombuses acting as bowtie nanoantennas. We consider the effect of sharp tips and the proximity effect on the electromagnetic field concentration in such low-loss metasurfaces. Our structures have the advantage of very low absorption losses with an order of magnitude field enhancement and the virtue of full compatibility with the standard planar technologies. This makes them convenient for various practical applications which integrate high field concentration with e.g. waveguiding properties, for instance microreactors, labs-on-a-chip, photocatalytic systems and various other Micro-Opto-Electro-Mechanical System (MOEMS) devices integrating optical, microfluidic and other functionalities.
2019 International Semiconductor Conference (CAS)
Plasmonic metamaterials offer a multitude of different applications. A limitation to their wider ... more Plasmonic metamaterials offer a multitude of different applications. A limitation to their wider use is high absorption. Here we consider an alternative solution in the form of silicon-silica nanocomposites to be used as metasurface-based optical concentrators with decreased losses. To this purpose we design and simulate arrays of bowtie nanoantennas, built in ultrathin silicon films on a silica substrate. In comparison to plasmonic structures, field localization is weaker. On the other hand, our structures have very low absorption losses and a full compatibility with standard planar technologies. This makes them convenient for microreactors, lab-on-a-chip devices and various microfluidic MEMS systems.
We present an analysis of noise currents in magnetoconcentration HgCdTe and InSb photodetectors w... more We present an analysis of noise currents in magnetoconcentration HgCdTe and InSb photodetectors with nonequilibrium suppression of Auger processes. These detectors are intended for the detection of infrared radiation in the (8-14) mm range at elevated temperatures and generation-recombination noise is the parameter limiting their performace. Its suppression is essential for the proper operation of these detectors. We also shortly consider 1/f (flicker) noise and the influence of magnetic field on its value.
In this paper we propose a novel operating principle for thermal vacuum sensor. The sensor consid... more In this paper we propose a novel operating principle for thermal vacuum sensor. The sensor considered in this work consists of thermopiles and thermally isolating membrane structure. The operating principle of such sensor would be based on monitoring thermal time constant dependence on pressure. In order to get the most prominent effect, sensor fabricated on SOI wafer is studied. Simulation was performed using 1D analytical model. It is shown that sensors performance could be improved by increasing the number of thermocouples. Apart from that it is demonstrated that performance of such sensor depends also on gas present in the housing so the same device could be also used as a gas type detector.
Solid State Phenomena, 1998
We performed an analysis of the absorption coefficient and refractive index in mercury cadmium te... more We performed an analysis of the absorption coefficient and refractive index in mercury cadmium telluride single crystalline layers fabricated by liquid phase and vapor phase epitaxy for a large number of samples with different compositions (0.165<x<0.3) and degrees of carrier degeneracy (n < 10^19 cm^-3). The transmission of samples was measured by LWIR (long wavelength infrared) spectrometry, and carrier concentration was determined by the Hall method. In our analysis of the measured results we used the generalized model of infrared absorption in mercury cadmium telluride, where the interband absorption was calculated using the Kane kP approach which takes into account the Urbach band tailing, the non parabolicity of bands and the Moss-Burstein bandfilling effect, and we also applied our approximate relations based on this model. In the long wavelength region, we took into account the absorption on free carriers. To calculate the values of the transmission coefficient we used a multilayer thin film approach. The connection between the real part of the refractive index and the infrared absorption coefficient was determined using the Kramers-Kronig relations and by applying empirical models.