We present a key idea of using the graphene-based Schottky junction to achieve high sensitivity a... more We present a key idea of using the graphene-based Schottky junction to achieve high sensitivity and wide
detection range radiation sensors. Nanostructured Schottky junction is formed at the interface between
a graphene, metal electrode, and a semiconductor. The current flowing through the junction is mainly
controlled by the barrier’s height and width. Therefore, the detection principle is based on Schottky
barrier height (SBH) modulation in response to different materials and stimuli. We have illustrated the
concept for gamma () radiation sensors. It’s demonstrated that the integration of graphene leads to a
great enhancement in sensitivity of up to 11 times coupled with 5 times increase in the sensing range
as compared to conventional Schottky junctions. Furthermore, it was demonstrated that for proposed
sensors, that the change in SBH could be fairly linearized as a function in the radiation dose unlike the
SBH of comparable conventional junctions. The new concept opens the door for a novel class of minitiuarized,
low biased, nanoscale radiation sensors for wireless sensor networks. The devices are based on
new nanostructured Schottky junctions made by growing graphene on ultrathin platinum catalytic layer
grown on different silicon substrates. Graphene high uniformity film with small flakes size embedded
with platinum particles was synthesized using two deposition steps. The integration of graphene layers
on regular M–S junctions was only possible by using an ALD grown platinum thin film (10–40 nm)
and then growing graphene in PECVD at temperatures lower than platinum silicide formation temperature.
The radiation sensing behaviors were investigated using two different substrate types. The first
substrate type is a moderately doped n-type (n≈2×1015 cm−3) silicon substrate in which a Schottky
rectifier response with different threshold voltages was observed. A device that is based on Pt/n-Si conventional
Schottky junction was used as a reference. The various devices were exposed to a range of
-irradiations (2–120 kGy) using Co60 source, and a change in terminal voltages before and after radiation
were measured accordingly. A sensitivity of 3.259A/kGycm2 at 1V bias over a wide detection range
has been realized. The charge transport mechanisms are interpreted on the basis of testing the detectors
at elevated temperatures and theoretical models, both of which both verified tunneling as the dominant
charge transport in the device. Tunneling allowed the operation of the detectors at low bias voltages with
good sensitivity. The detector’s realized sensitivity at low bias voltage is a significant advantage, allowing
the sensor to operate on a small battery or an energy-harvesting source. This is ideal for low-cost wireless
sensor networks.
The obtained responses, increase in sensitivity, and increase in detection range, were explained by
studying the band diagrams of the graphene–Schottky junction in comparison to that of the conventional
junction. Further, the fact that graphene layer was grown on the M–S junction adds to the uniqueness
of this research since exfoliated graphene will result in increased contact resistance and lower carrier
mobility which might not yield the desired sensing response.
This work focuses on establishing the scientific and engineering foundations for the design and m... more This work focuses on establishing the scientific and engineering foundations for the design and modeling of novel microcellular acoustical polymeric and ceramic foams and gaining a fundamental understanding of the mechanisms and critical parameters governing their sound absorption behavior. The presented research is particularly intended to broaden the knowledge in the fields of understanding the effects of structure and morphology on the acoustical behavior of microcellular foams. In this context, an attempt has been made to establish rigorous, experimentally validated, theoretical models that describe the phenomena and increase the accuracy of the current sound propagation models by integrating the structure and morphology effects to them for better design of acoustical materials. The major contributions of this thesis include: (i) development of the relation between foaming process parameters and the generated microcellular structure and morphology, (ii) characterization of the c...
In this paper, we aim to demonstrate a novel scheme for integration of nanostructured semiconduct... more In this paper, we aim to demonstrate a novel scheme for integration of nanostructured semiconductor Graphene Oxide (GO) shottky diodes on flexible substrate for a wide range of sensing applications. The platform introduces a novel flexible GO/Pt/n-Si and GO/Pt/SiN composite structures which provides excellent optical and electrical properties, while maintaining an acceptable mechanical, biocompatibility, and return loss performance. The new structure was investigated for glucose, radiation, and infrared sensing. The sensors results showed ultrahigh sensitivity and high linearity in the targeted regions of interest. Moreover, the use of nanostructured materials allows for the development of a new generation of modern printed circuit antennas and will enable wide range of applications merging both technologies for a wide range of wearable and implantable sensing devices.
Proceedings International Conference on MEMS, NANO and Smart Systems, 2003
ABSTRACT For pt.I, see ibid., no.3, p.015-021 (2003). The finite element procedure proposed in pa... more ABSTRACT For pt.I, see ibid., no.3, p.015-021 (2003). The finite element procedure proposed in part I was successfully used to model a smart-self-damage control system consisted of SMA wires embedded in a polymeric matrix. A parametric study was performed to investigate the effect of various parameters on the performance of the system. It was found that increasing current density speeds up the recovery process although it adds more heat to the system. Also, it was found that increasing wire diameters although speeds up the recovery process as well, it might cause harmful effects to the system by increasing the difference in CTE forces effect. Increasing number of activated wires was found to be beneficial as it reduces the amount of phase transformation and forces required per wire, and increases system sensitivity to small cracks. It is suggested that convection coefficient not to be too low or to high, and the initial temperature of the system to be as close to the Austenite start temperature as possible. It was also found that SMA wires prestraining have negligible effects if its not too low.
ABSTRACT This paper discusses the control of the foaming process for production of variable micro... more ABSTRACT This paper discusses the control of the foaming process for production of variable microcellular structures and morphologies for novel acoustical foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Crosslinked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9×10 3 - 1.6×10 9 cells/cm 3) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced.
ABSTRACT This paper discusses the development of lighter weight, superior acoustic performance an... more ABSTRACT This paper discusses the development of lighter weight, superior acoustic performance and cost effective viscoelastic microcellular foams for the use in automotive passive noise control panels. The study incorporates the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Cross linked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9E10 8 - 1.6E10 9 cells/cm 3 ) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced.
ABSTRACT A novel processing method for fabricating high porosity microcellular ceramic foams for ... more ABSTRACT A novel processing method for fabricating high porosity microcellular ceramic foams for sound absorption applications has been developed. The strategy for fabricating the ceramic foams involves: (i) forming some shapes using a mixture of preceramic polymer and expandable microspheres by a conventional ceramic forming method, (ii) foaming the compact by heating, (iii) cross-linking the foamed body, and (iv) transforming the foamed body into ceramic foams by pyrolysis. By controlling the microsphere content and that of the base elastomer, it was possible to adjust the porosity with a very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9 x 10⁸ ? 1.6 x 109 cells/cm₃) and desired expansion ratios (3 - 6 folds). Sound absorption testing has been performed using ASTM C-384 standard test. The preliminary results show that ceramic foams are candidate sound absorption materials.
We present a key idea of using the graphene-based Schottky junction to achieve high sensitivity a... more We present a key idea of using the graphene-based Schottky junction to achieve high sensitivity and wide
detection range radiation sensors. Nanostructured Schottky junction is formed at the interface between
a graphene, metal electrode, and a semiconductor. The current flowing through the junction is mainly
controlled by the barrier’s height and width. Therefore, the detection principle is based on Schottky
barrier height (SBH) modulation in response to different materials and stimuli. We have illustrated the
concept for gamma () radiation sensors. It’s demonstrated that the integration of graphene leads to a
great enhancement in sensitivity of up to 11 times coupled with 5 times increase in the sensing range
as compared to conventional Schottky junctions. Furthermore, it was demonstrated that for proposed
sensors, that the change in SBH could be fairly linearized as a function in the radiation dose unlike the
SBH of comparable conventional junctions. The new concept opens the door for a novel class of minitiuarized,
low biased, nanoscale radiation sensors for wireless sensor networks. The devices are based on
new nanostructured Schottky junctions made by growing graphene on ultrathin platinum catalytic layer
grown on different silicon substrates. Graphene high uniformity film with small flakes size embedded
with platinum particles was synthesized using two deposition steps. The integration of graphene layers
on regular M–S junctions was only possible by using an ALD grown platinum thin film (10–40 nm)
and then growing graphene in PECVD at temperatures lower than platinum silicide formation temperature.
The radiation sensing behaviors were investigated using two different substrate types. The first
substrate type is a moderately doped n-type (n≈2×1015 cm−3) silicon substrate in which a Schottky
rectifier response with different threshold voltages was observed. A device that is based on Pt/n-Si conventional
Schottky junction was used as a reference. The various devices were exposed to a range of
-irradiations (2–120 kGy) using Co60 source, and a change in terminal voltages before and after radiation
were measured accordingly. A sensitivity of 3.259A/kGycm2 at 1V bias over a wide detection range
has been realized. The charge transport mechanisms are interpreted on the basis of testing the detectors
at elevated temperatures and theoretical models, both of which both verified tunneling as the dominant
charge transport in the device. Tunneling allowed the operation of the detectors at low bias voltages with
good sensitivity. The detector’s realized sensitivity at low bias voltage is a significant advantage, allowing
the sensor to operate on a small battery or an energy-harvesting source. This is ideal for low-cost wireless
sensor networks.
The obtained responses, increase in sensitivity, and increase in detection range, were explained by
studying the band diagrams of the graphene–Schottky junction in comparison to that of the conventional
junction. Further, the fact that graphene layer was grown on the M–S junction adds to the uniqueness
of this research since exfoliated graphene will result in increased contact resistance and lower carrier
mobility which might not yield the desired sensing response.
This work focuses on establishing the scientific and engineering foundations for the design and m... more This work focuses on establishing the scientific and engineering foundations for the design and modeling of novel microcellular acoustical polymeric and ceramic foams and gaining a fundamental understanding of the mechanisms and critical parameters governing their sound absorption behavior. The presented research is particularly intended to broaden the knowledge in the fields of understanding the effects of structure and morphology on the acoustical behavior of microcellular foams. In this context, an attempt has been made to establish rigorous, experimentally validated, theoretical models that describe the phenomena and increase the accuracy of the current sound propagation models by integrating the structure and morphology effects to them for better design of acoustical materials. The major contributions of this thesis include: (i) development of the relation between foaming process parameters and the generated microcellular structure and morphology, (ii) characterization of the c...
In this paper, we aim to demonstrate a novel scheme for integration of nanostructured semiconduct... more In this paper, we aim to demonstrate a novel scheme for integration of nanostructured semiconductor Graphene Oxide (GO) shottky diodes on flexible substrate for a wide range of sensing applications. The platform introduces a novel flexible GO/Pt/n-Si and GO/Pt/SiN composite structures which provides excellent optical and electrical properties, while maintaining an acceptable mechanical, biocompatibility, and return loss performance. The new structure was investigated for glucose, radiation, and infrared sensing. The sensors results showed ultrahigh sensitivity and high linearity in the targeted regions of interest. Moreover, the use of nanostructured materials allows for the development of a new generation of modern printed circuit antennas and will enable wide range of applications merging both technologies for a wide range of wearable and implantable sensing devices.
Proceedings International Conference on MEMS, NANO and Smart Systems, 2003
ABSTRACT For pt.I, see ibid., no.3, p.015-021 (2003). The finite element procedure proposed in pa... more ABSTRACT For pt.I, see ibid., no.3, p.015-021 (2003). The finite element procedure proposed in part I was successfully used to model a smart-self-damage control system consisted of SMA wires embedded in a polymeric matrix. A parametric study was performed to investigate the effect of various parameters on the performance of the system. It was found that increasing current density speeds up the recovery process although it adds more heat to the system. Also, it was found that increasing wire diameters although speeds up the recovery process as well, it might cause harmful effects to the system by increasing the difference in CTE forces effect. Increasing number of activated wires was found to be beneficial as it reduces the amount of phase transformation and forces required per wire, and increases system sensitivity to small cracks. It is suggested that convection coefficient not to be too low or to high, and the initial temperature of the system to be as close to the Austenite start temperature as possible. It was also found that SMA wires prestraining have negligible effects if its not too low.
ABSTRACT This paper discusses the control of the foaming process for production of variable micro... more ABSTRACT This paper discusses the control of the foaming process for production of variable microcellular structures and morphologies for novel acoustical foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Crosslinked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9×10 3 - 1.6×10 9 cells/cm 3) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced.
ABSTRACT This paper discusses the development of lighter weight, superior acoustic performance an... more ABSTRACT This paper discusses the development of lighter weight, superior acoustic performance and cost effective viscoelastic microcellular foams for the use in automotive passive noise control panels. The study incorporates the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Cross linked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9E10 8 - 1.6E10 9 cells/cm 3 ) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced.
ABSTRACT A novel processing method for fabricating high porosity microcellular ceramic foams for ... more ABSTRACT A novel processing method for fabricating high porosity microcellular ceramic foams for sound absorption applications has been developed. The strategy for fabricating the ceramic foams involves: (i) forming some shapes using a mixture of preceramic polymer and expandable microspheres by a conventional ceramic forming method, (ii) foaming the compact by heating, (iii) cross-linking the foamed body, and (iv) transforming the foamed body into ceramic foams by pyrolysis. By controlling the microsphere content and that of the base elastomer, it was possible to adjust the porosity with a very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9 x 10⁸ ? 1.6 x 109 cells/cm₃) and desired expansion ratios (3 - 6 folds). Sound absorption testing has been performed using ASTM C-384 standard test. The preliminary results show that ceramic foams are candidate sound absorption materials.
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Papers by Mohamed Serry
detection range radiation sensors. Nanostructured Schottky junction is formed at the interface between
a graphene, metal electrode, and a semiconductor. The current flowing through the junction is mainly
controlled by the barrier’s height and width. Therefore, the detection principle is based on Schottky
barrier height (SBH) modulation in response to different materials and stimuli. We have illustrated the
concept for gamma () radiation sensors. It’s demonstrated that the integration of graphene leads to a
great enhancement in sensitivity of up to 11 times coupled with 5 times increase in the sensing range
as compared to conventional Schottky junctions. Furthermore, it was demonstrated that for proposed
sensors, that the change in SBH could be fairly linearized as a function in the radiation dose unlike the
SBH of comparable conventional junctions. The new concept opens the door for a novel class of minitiuarized,
low biased, nanoscale radiation sensors for wireless sensor networks. The devices are based on
new nanostructured Schottky junctions made by growing graphene on ultrathin platinum catalytic layer
grown on different silicon substrates. Graphene high uniformity film with small flakes size embedded
with platinum particles was synthesized using two deposition steps. The integration of graphene layers
on regular M–S junctions was only possible by using an ALD grown platinum thin film (10–40 nm)
and then growing graphene in PECVD at temperatures lower than platinum silicide formation temperature.
The radiation sensing behaviors were investigated using two different substrate types. The first
substrate type is a moderately doped n-type (n≈2×1015 cm−3) silicon substrate in which a Schottky
rectifier response with different threshold voltages was observed. A device that is based on Pt/n-Si conventional
Schottky junction was used as a reference. The various devices were exposed to a range of
-irradiations (2–120 kGy) using Co60 source, and a change in terminal voltages before and after radiation
were measured accordingly. A sensitivity of 3.259A/kGycm2 at 1V bias over a wide detection range
has been realized. The charge transport mechanisms are interpreted on the basis of testing the detectors
at elevated temperatures and theoretical models, both of which both verified tunneling as the dominant
charge transport in the device. Tunneling allowed the operation of the detectors at low bias voltages with
good sensitivity. The detector’s realized sensitivity at low bias voltage is a significant advantage, allowing
the sensor to operate on a small battery or an energy-harvesting source. This is ideal for low-cost wireless
sensor networks.
The obtained responses, increase in sensitivity, and increase in detection range, were explained by
studying the band diagrams of the graphene–Schottky junction in comparison to that of the conventional
junction. Further, the fact that graphene layer was grown on the M–S junction adds to the uniqueness
of this research since exfoliated graphene will result in increased contact resistance and lower carrier
mobility which might not yield the desired sensing response.
detection range radiation sensors. Nanostructured Schottky junction is formed at the interface between
a graphene, metal electrode, and a semiconductor. The current flowing through the junction is mainly
controlled by the barrier’s height and width. Therefore, the detection principle is based on Schottky
barrier height (SBH) modulation in response to different materials and stimuli. We have illustrated the
concept for gamma () radiation sensors. It’s demonstrated that the integration of graphene leads to a
great enhancement in sensitivity of up to 11 times coupled with 5 times increase in the sensing range
as compared to conventional Schottky junctions. Furthermore, it was demonstrated that for proposed
sensors, that the change in SBH could be fairly linearized as a function in the radiation dose unlike the
SBH of comparable conventional junctions. The new concept opens the door for a novel class of minitiuarized,
low biased, nanoscale radiation sensors for wireless sensor networks. The devices are based on
new nanostructured Schottky junctions made by growing graphene on ultrathin platinum catalytic layer
grown on different silicon substrates. Graphene high uniformity film with small flakes size embedded
with platinum particles was synthesized using two deposition steps. The integration of graphene layers
on regular M–S junctions was only possible by using an ALD grown platinum thin film (10–40 nm)
and then growing graphene in PECVD at temperatures lower than platinum silicide formation temperature.
The radiation sensing behaviors were investigated using two different substrate types. The first
substrate type is a moderately doped n-type (n≈2×1015 cm−3) silicon substrate in which a Schottky
rectifier response with different threshold voltages was observed. A device that is based on Pt/n-Si conventional
Schottky junction was used as a reference. The various devices were exposed to a range of
-irradiations (2–120 kGy) using Co60 source, and a change in terminal voltages before and after radiation
were measured accordingly. A sensitivity of 3.259A/kGycm2 at 1V bias over a wide detection range
has been realized. The charge transport mechanisms are interpreted on the basis of testing the detectors
at elevated temperatures and theoretical models, both of which both verified tunneling as the dominant
charge transport in the device. Tunneling allowed the operation of the detectors at low bias voltages with
good sensitivity. The detector’s realized sensitivity at low bias voltage is a significant advantage, allowing
the sensor to operate on a small battery or an energy-harvesting source. This is ideal for low-cost wireless
sensor networks.
The obtained responses, increase in sensitivity, and increase in detection range, were explained by
studying the band diagrams of the graphene–Schottky junction in comparison to that of the conventional
junction. Further, the fact that graphene layer was grown on the M–S junction adds to the uniqueness
of this research since exfoliated graphene will result in increased contact resistance and lower carrier
mobility which might not yield the desired sensing response.