Papers by Natalia Maksimchuk
Nanotechnologies in Russia, 2010
The influence of the technical parameters of nanostructured CeO x film production on electronic, ... more The influence of the technical parameters of nanostructured CeO x film production on electronic, structural, optical, and photoelectronic characteristics has been studied for their practical application as the active element of various microelectronic sensors-such as high performance photoresistors, MOS photo diodes for bioluminescence registration, ion selective field effect transistor (ISFETs), and MOS varactors indicating pH changing as a result of biochemical processes. X ray photoelectron spectroscopy analysis (XPS) has shown that the ratio of Ce 3+ and Ce 4+ ions in CeO x films has changed, depending on the techno logical regime and, first and foremost, on the temperature of the substrate, which results in an changing of the fundamental gap width. The correlation between these alterations and the optical and photoelectric char acteristics has been determined. On the basis of highly sensitive photo photoreceivers and living organisms (daphnia and bioluminescence bacteria), a portative electron bioluminescent metric complex has been cre ated to determine the overall water toxicity caused by mycotoxin patulin, biphentrin, and chlorpyrifos. The minimal sensitivity threshold for patulin is 0.1 mg/l after a 2 h experiment and 0.01 mg/l after 6 and 24 h experiments; for biphentrin, it is 0.01 mg/l after a 3 h experiment and 0.0001 mg/l after a 24 h experiment. It is shown that applying nanocrystalline films of cerium oxide CeO x as the dielectric of MOS structures increases the sensitivity and stability of these sensors due to the high density of the surface of sensitive centers of CeO x (to 10 20 m-2), the high values of dielectric permeability (ε = 26) and the band gap width (3.6 eV), and low values of leakage currents. The results of ISFET and MOS varactor application with nanocrystalline CeO x film for the creation of immune and enzymatic biosensors have been demonstrated. The sensitivity threshold of an enzymatic sensor based on choline esterase to organophosphorous pesticides is 10-9 M, and for ions of heavy metals it is 10-7 M. The pH sensitivity of ISFET is 58 mV/pH, which is close to the maximal possible sensitivity for the semiconductor-dielectric-solution structure (the so called Nernst sensitivity is 59 mV/pH).
2015 IEEE 35th International Conference on Electronics and Nanotechnology (ELNANO), 2015
Nanocrystalline CeOx film in the Al/nc-CeOx /Si-Al structures has been obtained using flash evapo... more Nanocrystalline CeOx film in the Al/nc-CeOx /Si-Al structures has been obtained using flash evaporation method and method of metallic Ce oxidation. The electrophysical properties of the Al/nc-CeOx /Si/Al structures and the effect of technological factors on these properties have been investigated. It was revealed that the nanocrystalline CeOx layer in the Al/nc-CeOx /Si/Al structures is a semiconductor with an electronic conductivity and volume resistivity is within the range of 0.5-30 MΩ·cm. Based on the synthesized Al/nc-CeO x /Si/Al structures the new types of heterojunction diodes with high interface quality have been developed. Interface state density of obtained structures is of about 7·10^10 cm^(-2) ·eV^(-1)
Al/nanocrystalline CeOx/Si/Al structures have been
obtained using flash evaporation method. The e... more Al/nanocrystalline CeOx/Si/Al structures have been
obtained using flash evaporation method. The effect of
technological factors (substrate temperature and type) on the
CeOx films microstructure as well as on photoelectric properties
of the Al/nc-CeOx/Si/Al structures has been investigated. The
method of high-frequency C-V characteristics was used to study
the cerium oxide film/singlecrystalline silicon interface.
On the basis of the synthesized nanocrystalline (nc) СеОх films
obtained by the flash method we have developed new types of
heterojunction photodetectors with enhanced photosensitivity
(330 μA/lm∙V) in the visible range. A stable metal/nc-CeOx/Si
structures have been received that reveal an interface state desity
of 7∙1010 cm-2∙eV-1 and a DC dielectric constant of about 15.
The influence of the technical parameters of nanostructured CeOx film production on electronic,
s... more The influence of the technical parameters of nanostructured CeOx film production on electronic,
structural, optical, and photoelectronic characteristics has been studied for their practical application as the
active element of various microelectronic sensors—such as highperformance photoresistors, MOSphoto
diodes for bioluminescence registration, ionselective fieldeffect transistor (ISFETs), and MOSvaractors
indicating pH changing as a result of biochemical processes. Xray photoelectron spectroscopy analysis
(XPS) has shown that the ratio of Ce3+ and Ce4+ ions in CeOx films has changed, depending on the techno
logical regime and, first and foremost, on the temperature of the substrate, which results in an changing of
the fundamental gap width. The correlation between these alterations and the optical and photoelectric char
acteristics has been determined. On the basis of highly sensitive photo photoreceivers and living organisms
(daphnia and bioluminescence bacteria), a portative electron bioluminescent metric complex has been cre
ated to determine the overall water toxicity caused by mycotoxin patulin, biphentrin, and chlorpyrifos. The
minimal sensitivity threshold for patulin is 0.1 mg/l after a 2 h experiment and 0.01 mg/l after 6 and 24 h
experiments; for biphentrin, it is 0.01 mg/l after a 3 h experiment and 0.0001 mg/l after a 24 h experiment. It
is shown that applying nanocrystalline films of cerium oxide CeOx as the dielectric of MOS structures
increases the sensitivity and stability of these sensors due to the high density of the surface of sensitive centers
of CeOx (to 1020 m–2), the high values of dielectric permeability (ε = 26) and the bandgap width (3.6 eV),
and low values of leakage currents. The results of ISFET and MOS varactor application with nanocrystalline
CeOx film for the creation of immune and enzymatic biosensors have been demonstrated. The sensitivity threshold
of an enzymatic sensor based on choline esterase to organophosphorous pesticides is 10–9 M, and for ions of heavy
metals it is 10–7 M. The pH sensitivity of ISFET is 58 mV/pH, which is close to the maximal possible sensitivity
for the semiconductor–dielectric–solution structure (the socalled Nernst sensitivity is 59 mV/pH).
The physical properties of thin nanocrystalline cerium oxide films have been studied with the pur... more The physical properties of thin nanocrystalline cerium oxide films have been studied with the purpose of their application as a functional material of different microelectronic transducers for biosensors: highperformance photoresistors and photodiodes for bioluminescence registration, ion-selective field-effect transistors (ISFET) and MOS-varactors indicating the pH changes as a result of biochemical processes. The effect of technological factors on the photoelectrical, optical, temperature and electrophysical properties of cerium oxide films has been studied. We established the technological conditions which allow to obtain СеОх-films with desired functional characteristics. On the basis of the synthesized nanocrystalline СеОх-films obtained by the "explosive evaporation" method we developed new types of photodetectors for registration of bioluminescent signal (photoresistors and photodiodes) with enhanced photosensitivity (310-330 mA/lm•V) in the visible range. Application of cerium oxide based photoresistors in the bioluminometers instead of photomultiplier tubes and avalanche photodiodes allows to significantly reduce the cost of bioluminometer and increase its sensitivity when measuring at alternating signal.
Conference Presentations by Natalia Maksimchuk
Excitation of surface plasmon resonances has been observed on laser-induced highlyregular
1D peri... more Excitation of surface plasmon resonances has been observed on laser-induced highlyregular
1D periodic Si surface covered with Au nanoparticles. The nanostructured surfaces open
new perspectives for production of photonic and plasmonic sensor elements.
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Papers by Natalia Maksimchuk
obtained using flash evaporation method. The effect of
technological factors (substrate temperature and type) on the
CeOx films microstructure as well as on photoelectric properties
of the Al/nc-CeOx/Si/Al structures has been investigated. The
method of high-frequency C-V characteristics was used to study
the cerium oxide film/singlecrystalline silicon interface.
On the basis of the synthesized nanocrystalline (nc) СеОх films
obtained by the flash method we have developed new types of
heterojunction photodetectors with enhanced photosensitivity
(330 μA/lm∙V) in the visible range. A stable metal/nc-CeOx/Si
structures have been received that reveal an interface state desity
of 7∙1010 cm-2∙eV-1 and a DC dielectric constant of about 15.
structural, optical, and photoelectronic characteristics has been studied for their practical application as the
active element of various microelectronic sensors—such as highperformance photoresistors, MOSphoto
diodes for bioluminescence registration, ionselective fieldeffect transistor (ISFETs), and MOSvaractors
indicating pH changing as a result of biochemical processes. Xray photoelectron spectroscopy analysis
(XPS) has shown that the ratio of Ce3+ and Ce4+ ions in CeOx films has changed, depending on the techno
logical regime and, first and foremost, on the temperature of the substrate, which results in an changing of
the fundamental gap width. The correlation between these alterations and the optical and photoelectric char
acteristics has been determined. On the basis of highly sensitive photo photoreceivers and living organisms
(daphnia and bioluminescence bacteria), a portative electron bioluminescent metric complex has been cre
ated to determine the overall water toxicity caused by mycotoxin patulin, biphentrin, and chlorpyrifos. The
minimal sensitivity threshold for patulin is 0.1 mg/l after a 2 h experiment and 0.01 mg/l after 6 and 24 h
experiments; for biphentrin, it is 0.01 mg/l after a 3 h experiment and 0.0001 mg/l after a 24 h experiment. It
is shown that applying nanocrystalline films of cerium oxide CeOx as the dielectric of MOS structures
increases the sensitivity and stability of these sensors due to the high density of the surface of sensitive centers
of CeOx (to 1020 m–2), the high values of dielectric permeability (ε = 26) and the bandgap width (3.6 eV),
and low values of leakage currents. The results of ISFET and MOS varactor application with nanocrystalline
CeOx film for the creation of immune and enzymatic biosensors have been demonstrated. The sensitivity threshold
of an enzymatic sensor based on choline esterase to organophosphorous pesticides is 10–9 M, and for ions of heavy
metals it is 10–7 M. The pH sensitivity of ISFET is 58 mV/pH, which is close to the maximal possible sensitivity
for the semiconductor–dielectric–solution structure (the socalled Nernst sensitivity is 59 mV/pH).
Conference Presentations by Natalia Maksimchuk
1D periodic Si surface covered with Au nanoparticles. The nanostructured surfaces open
new perspectives for production of photonic and plasmonic sensor elements.
obtained using flash evaporation method. The effect of
technological factors (substrate temperature and type) on the
CeOx films microstructure as well as on photoelectric properties
of the Al/nc-CeOx/Si/Al structures has been investigated. The
method of high-frequency C-V characteristics was used to study
the cerium oxide film/singlecrystalline silicon interface.
On the basis of the synthesized nanocrystalline (nc) СеОх films
obtained by the flash method we have developed new types of
heterojunction photodetectors with enhanced photosensitivity
(330 μA/lm∙V) in the visible range. A stable metal/nc-CeOx/Si
structures have been received that reveal an interface state desity
of 7∙1010 cm-2∙eV-1 and a DC dielectric constant of about 15.
structural, optical, and photoelectronic characteristics has been studied for their practical application as the
active element of various microelectronic sensors—such as highperformance photoresistors, MOSphoto
diodes for bioluminescence registration, ionselective fieldeffect transistor (ISFETs), and MOSvaractors
indicating pH changing as a result of biochemical processes. Xray photoelectron spectroscopy analysis
(XPS) has shown that the ratio of Ce3+ and Ce4+ ions in CeOx films has changed, depending on the techno
logical regime and, first and foremost, on the temperature of the substrate, which results in an changing of
the fundamental gap width. The correlation between these alterations and the optical and photoelectric char
acteristics has been determined. On the basis of highly sensitive photo photoreceivers and living organisms
(daphnia and bioluminescence bacteria), a portative electron bioluminescent metric complex has been cre
ated to determine the overall water toxicity caused by mycotoxin patulin, biphentrin, and chlorpyrifos. The
minimal sensitivity threshold for patulin is 0.1 mg/l after a 2 h experiment and 0.01 mg/l after 6 and 24 h
experiments; for biphentrin, it is 0.01 mg/l after a 3 h experiment and 0.0001 mg/l after a 24 h experiment. It
is shown that applying nanocrystalline films of cerium oxide CeOx as the dielectric of MOS structures
increases the sensitivity and stability of these sensors due to the high density of the surface of sensitive centers
of CeOx (to 1020 m–2), the high values of dielectric permeability (ε = 26) and the bandgap width (3.6 eV),
and low values of leakage currents. The results of ISFET and MOS varactor application with nanocrystalline
CeOx film for the creation of immune and enzymatic biosensors have been demonstrated. The sensitivity threshold
of an enzymatic sensor based on choline esterase to organophosphorous pesticides is 10–9 M, and for ions of heavy
metals it is 10–7 M. The pH sensitivity of ISFET is 58 mV/pH, which is close to the maximal possible sensitivity
for the semiconductor–dielectric–solution structure (the socalled Nernst sensitivity is 59 mV/pH).
1D periodic Si surface covered with Au nanoparticles. The nanostructured surfaces open
new perspectives for production of photonic and plasmonic sensor elements.