2018 18th International Workshop on Junction Technology (IWJT), 2018
Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silic... more Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silicon as a device substrate for a high-performance device. Further optimization on fabrication process parameters in germanium involving ion-implantation and thermal annealing is important to form a highly activated np junction. Co-implantation technique has prompted interest due to its reported stress-induced activation; which may be due to the implementation of two atoms different in size. Combining with ultra-fast/high temperature of laser thermal annealing may promotes the improvement in activation and damage removal. This works focused on introducing stress to the germanium substrate through co-implantation of dopant ions, follows by laser thermal annealing to activate and remove the implanted damages. It is found that Raman shift of the annealed co-implanted sample can be observed with 0.2% increase in the strain value, when comparing to the single implanted sample. 12% improvement of sheet resistance can also be observed, which may be related due to the increase in stress.
2017 17th International Workshop on Junction Technology (IWJT), 2017
Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobili... more Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobility, which is the key point for realizing device high-drive-current. However, fabricating highly activated np junction in Ge is challenging due to the severe damages introduced from ion-implantation interact with dopant during subsequent annealing process, and results in dopant deactivation. Further optimization of fabrication process parameters is needed to overcome this problem. Co-implantation technique has gained attention due to its stress-induced carrier activation by implanting two atoms with different size. Combining with laser thermal annealing promise further improvement in activation and recrystallization. In this work, co-implantation of phosphorus (P) and tin (Sn) were performed, followed by KrF laser thermal annealing, to form an np junction in Ge. Laser fluence was varied to achieve np junction with higher activation and recrystallization. It is found that high degree of re...
2016 IEEE Industrial Electronics and Applications Conference (IEACon), 2016
Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Furt... more Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Further optimization in ion implantation process parameters is required in order to fabricate highly activated n-type junction in Ge. The co-implantation technique is one of interest due to the enhanced active carrier concentration attributed to the stress associated with atomic size of the non-dopant. In this work, phosphorus (P) and tin (Sn) have been selected as dopant and non-dopant atoms for the co-implantation process. Theoretical analysis on dopant distribution in the substrate was performed using TRIM software. The calculation predicted a maximum concentration of n-type dopant up to 1E20 cm−3. Fabricated samples were then experimentally analyzed using SIMS for depth profiling. A difference of less than one order of magnitude was observed from the comparison of both results. The difference between TRIM and SIMS is attributed to the sputtering effect and the rise of temperature during ...
2020 IEEE International Conference on Semiconductor Electronics (ICSE), 2020
One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with... more One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with high-mobility material of germanium. However, fabrication of Ge np junction faces low dopant activation problem due to the interaction between dopant and defect that was originated from ion implantation, during thermal annealing process results in dopant deactivation. Eventually, series resistance of np junction between source and drain regions will increase and affect the device drive current. Therefore, minimizing junction resistance remains an important issue to be solved. In this work, ultrafast/high temperature excimer laser of KrF was adopted for post-implantation annealing process in order to achieve high activation level. Laser energy fluences and shot numbers were varied between 100–2000 mJ/cm2 and 1–1000 shots, respectively to investigate the influence of laser parameter to the np junction resistance value, surface morphology and recrystallization. It is found that resistance ...
Journal of Materials Science: Materials in Electronics, 2021
The material cannot be used for any other purpose without further permission of the publisher and... more The material cannot be used for any other purpose without further permission of the publisher and is for private use only. There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.
The authors regret that the name of an important author, Dr. Zhongbiao Wu, who has contributed to... more The authors regret that the name of an important author, Dr. Zhongbiao Wu, who has contributed to this work was unintentionally omitted in the author list during the multi-institutional collaborations which involves intensive communications. Dr. Wu is the supervisor of Zhuxing Sun (the co-first author of this work) and has contributed significantly in drafting and revising this manuscript, and as such he should be included in the authorship.
IOP Conference Series: Materials Science and Engineering, 2017
Germanium (Ge) has re-emerged as a potential candidate to replace silicon (Si) as a substrate, du... more Germanium (Ge) has re-emerged as a potential candidate to replace silicon (Si) as a substrate, due to its higher carrier mobility properties that are the key point for the realization of devices high drive current. However, the fabrication process of Ge is confronted with many problems such as low dopant electrical activation and the utilization of heavy n-type dopant atoms during ion implantation. These problems result in more damage and defects that can affect dopant activation. This paper reports the electrical and structural analysis on the formation of ntype junction in Ge substrate by ion implantation, followed by excimer laser annealing (ELA) using KrF laser. ELA parameters such as laser fluences were varied from 100-2000 mJ/cm 2 and shot number between 1-1000 to obtain the optimized parameter of ELA with a high degree of damage and defect removal. Low resistance with a high degree of crystallinity is obtained for the samples annealed with less than five shot number. Higher shot number with high laser fluence, shows a high degree of ablation damage.
International Symposium on Electromagnetic Compatibility, Aug 21, 2000
The calculation of induced current on wires is important if equipment immunity to electromagnetic... more The calculation of induced current on wires is important if equipment immunity to electromagnetic hazards is to be assessed by numerical modelling. Differential techniques in the time domain are attractive for dealing with EMC calculations over a wide frequency range that involve complex geometries. This paper discusses the "in-cell" inductance and capacitance thin wire model currently used in the transmission line matrix (TLM) and finite difference time domain (FDTD) techniques. The performance of these models is assessed using some simple examples and comparison with method of moments calculations. It is concluded that care needs to be taken when using these models and the accuracy that can be obtained depends upon the proximity of the wires to conducting surfaces and other conductors.
Exceptional optical and electrical characteristics of graphene based materials attract significan... more Exceptional optical and electrical characteristics of graphene based materials attract significant interest of the researchers to develop sensing center of surface plasmon resonance (SPR) based sensors by graphene application. In this research carrier density variant in the form of conductance gradient on graphene based SPR sensor response is modeled. The molecular properties such as electro-negativity, molecular mass, effective group number and effective outer shell factor are engaged. In addition each factor effect in the cumulative carrier variation is explored analytically. The refractive index shift equation based on these factors is defined and related coefficients are proposed. Finally a semiempirical model for interpretation of changes in SPR curve is suggested and tested for some organic molecules.
Asia-Pacific Conference on Applied Electromagnetics, 2003. APACE 2003.
ABSTRACT Potentially differential methods in the time domain such as finite difference time domai... more ABSTRACT Potentially differential methods in the time domain such as finite difference time domain (FDTD) and transmission line matrix (TLM) are attractive for solving electrically large problems, as is often the case when carrying out computations for electromagnetic compatibility. FDTD algorithms that are second order accurate in time and space are inherently dispersive and anisotropic. This can potentially cause computational errors when considering electrically large problems. Using a fine mesh can reduce the numerical dispersion but significantly impacts on the computational resources required. FDTD schemes that are fourth order space and second order time significantly reduces the numerical dispersion with a minimal increase in computational requirements. Symmetrical condensed node TLM has also been used successfully to solve many electromagnetic problems. In this paper, a comparison is made for the dispersion in TLM, 2nd and 4th order FDTD when a Gaussian pulse is propagating in a WR90 waveguide. A waveguide was considered to be a good example to consider because the wave propagates at an angle to the axial direction that is frequency dependent. The results show that the TLM and 4th order FDTD exhibit significantly lower numerical dispersion than 2nd order FDTD, potentially making them suitable for the accurate solution of large scale EMC problems.
Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorp... more Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorption of biomolecule, is a way for SPR biosensor sensitivity enhancement. In this paper a graphene-based SPR biosensor with wavelength modulation will be presented. A few graphene layers added to a conventional gold thin film SPR biosensor leads to a drastic increase in sensitivity. This is due to the increased biomolecule adsorption in the graphene layers. In comparison to conventional SPR sensors this produces a large change in the index of refraction change at the metal-dielectric interface. In this paper, the reflection of light coupled into a SPR mode propagating along a thin Au-graphene layer surrounded by dielectric layers is simulated and it is compared with a conventional SPR sensor. The simulation of light reflection in wavelength modulation via MATLAB is illustrated.
There has been much recent interest in the application of plasmonics to improve the efficiency of... more There has been much recent interest in the application of plasmonics to improve the efficiency of silicon solar cells. In this paper we use finite difference time domain calculations to investigate the placement of hemispherical gold nanoparticles on the rear surface of a silicon solar cell. The results indicate that nanoparticles protruding into the silicon, rather than into air, have a larger scattering efficiency and diffuse scattering into the semiconductor. This finding could lead to improved light trapping within a thin silicon solar cell device.
A new class of three-component photocatalyst system is designed with plasmonic AuCu nanoprisms em... more A new class of three-component photocatalyst system is designed with plasmonic AuCu nanoprisms embedded between a porous single crystalline TiO 2 nanoplate thin film and dodecahedral zeolitic imidazolate frameworks (ZIF-8) nanoparticles for enhanced CO 2 photocatalytic reduction. The ZIF-8 plays a role of CO 2 capture to enhance the reactant concentration on the catalyst, while the AuCu nanoprism functions as an important mediator to improve the charge density at the interfaces and facilitate the charge transfer from TiO 2 to ZIF-8. The reactant CO 2 could be not only readily collected on the newly designed catalyst, but also more efficiently converted to CO and CH 4. As a result, compared to the reference sample of twocomponent system of TiO 2 and ZIF-8 with a CO 2 conversion rate of 12.5 µmol h-1. g-1 , the new three-component photocatalyst exhibited a nearly 7-fold improvement in CO 2 photocatalytic reduction performance with CO 2 conversion reaching an outstanding value of86.9 µmol h-1. g-1 , highlighting the importance of rational heterojunction design in facilitating reactant adsorption, charge transfer and reaction processes in photocatalysis.
New technological advancements in wireless networks have enlarged the number of connected devices... more New technological advancements in wireless networks have enlarged the number of connected devices. The unprecedented surge of data volume in wireless systems empowered by artificial intelligence (AI) opens up new horizons for providing ubiquitous data-driven intelligent services. Traditional cloudcentric machine learning (ML)-based services are implemented by centrally collecting datasets and training models. However, this conventional training technique encompasses two challenges: (i) high communication and energy cost and (ii) threatened data privacy. In this article, we introduce a comprehensive survey of the fundamentals and enabling technologies of federated learning (FL), a newly emerging technique coined to bring ML to the edge of wireless networks. Moreover, an extensive study is presented detailing various applications of FL in wireless networks and highlighting their challenges and limitations. The efficacy of FL is further explored with emerging prospective beyond fifth-generation (B5G) and sixth-generation (6G) communication systems. This survey aims to provide an overview of the state-ofthe-art FL applications in key wireless technologies that will serve as a foundation to establish a firm understanding of the topic. Lastly, we offer a road forward for future research directions. 1
Graphene possesses a high surface-to-volume ratio, which enables biomolecules to attach to it for... more Graphene possesses a high surface-to-volume ratio, which enables biomolecules to attach to it for bioelectronic applications. In this article, first, the classification and applications of bioelectronic devices are briefly reviewed. Then, recent work on real fabricated graphenebased bioelectronic devices as well as the analysis of their architecture and design using a computational approach to their charge transport properties are presented and discussed. A comparison to nongraphitic bioelectronic devices is also given. On the macroscale level, the design of devices is elaborated on the basis of a finite element analysis (FEA) approach, and the impact of design on the performance of the devices is discussed. On the nanoscale level, transport phenomena and their mechanisms for different design categories are elaborated on the basis of the density functional theory (DFT) and other quantum chemistry calculations. The calculated and measured charge transport properties of graphene-based bioelectronic devices are also compared with those of other available bioelectronic devices.
This study uses the combined visual and wireless information to make future wireless networks mor... more This study uses the combined visual and wireless information to make future wireless networks more reliable.
In this letter, we investigate the performance of reconfigurable intelligent surface (RIS)-assist... more In this letter, we investigate the performance of reconfigurable intelligent surface (RIS)-assisted communications, under the assumption of generalized Gaussian noise (GGN), over Rayleigh fading channels. Specifically, we consider an RIS, equipped with N reflecting elements, and derive a novel closedform expression for the symbol error rate (SER) of arbitrary modulation schemes. The usefulness of the derived new expression is that it can be used to capture the SER performance in the presence of special additive noise distributions such as Gamma, Laplacian, and Gaussian noise. These special cases are also considered and their associated asymptotic SER expressions are derived, and then employed to quantify the achievable diversity order of the system. The theoretical framework is corroborated by numerical results, which reveal that the shaping parameter of the GGN (α) has a negligible effect on the diversity order of RISassisted systems, particularly for large α values. Accordingly, the maximum achievable diversity order is determined by N. Index terms-Additive generalized Gaussian noise, error rate analysis, reconfigurable intelligent surfaces, Meijer's Gfunction. I. INTRODUCTION S MART radio environments, empowered by reconfigurable intelligent surfaces (RISs), are envisioned to revolutionize the design of wireless systems, since they offer the ability to control the propagation environment of electromagnetic waves through establishing desired channel responses. Unlike conventional transmission techniques, such as phased arrays, multi-antenna transmitters, and relays involving active components, RISs are composed of a large number of passive reflecting elements (REs), each is supported by the lowest number of small-sized, low-power, and inexpensive components [1]. With the aid of at least one smart controller, the amplitude and/or phase-shift of incident signals are manipulated at each RE in real time, allowing for a transformative control (i.e., scattering, reflection, absorption, and refraction) of the radio waves characteristics. To reap the full potentials brought by RIS and cater for their unique challenges, exploring the performance limits of RIS-assisted wireless communications analytically has become an active research topic [2]-[5]. Specifically, in [2], the error probability performance is investigated for RIS-assisted nonorthogonal multiple access (NOMA) and backscatter communication systems, respectively. Furthermore, [3] investigated the performance of RIS-assisted wireless systems, based on outage probability, symbol error rate, and ergodic capacity. Similarly, the ergodic capacity is studied in [4] for multipleantenna RIS-assisted systems. For two-way communications,
2018 18th International Workshop on Junction Technology (IWJT), 2018
Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silic... more Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silicon as a device substrate for a high-performance device. Further optimization on fabrication process parameters in germanium involving ion-implantation and thermal annealing is important to form a highly activated np junction. Co-implantation technique has prompted interest due to its reported stress-induced activation; which may be due to the implementation of two atoms different in size. Combining with ultra-fast/high temperature of laser thermal annealing may promotes the improvement in activation and damage removal. This works focused on introducing stress to the germanium substrate through co-implantation of dopant ions, follows by laser thermal annealing to activate and remove the implanted damages. It is found that Raman shift of the annealed co-implanted sample can be observed with 0.2% increase in the strain value, when comparing to the single implanted sample. 12% improvement of sheet resistance can also be observed, which may be related due to the increase in stress.
2017 17th International Workshop on Junction Technology (IWJT), 2017
Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobili... more Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobility, which is the key point for realizing device high-drive-current. However, fabricating highly activated np junction in Ge is challenging due to the severe damages introduced from ion-implantation interact with dopant during subsequent annealing process, and results in dopant deactivation. Further optimization of fabrication process parameters is needed to overcome this problem. Co-implantation technique has gained attention due to its stress-induced carrier activation by implanting two atoms with different size. Combining with laser thermal annealing promise further improvement in activation and recrystallization. In this work, co-implantation of phosphorus (P) and tin (Sn) were performed, followed by KrF laser thermal annealing, to form an np junction in Ge. Laser fluence was varied to achieve np junction with higher activation and recrystallization. It is found that high degree of re...
2016 IEEE Industrial Electronics and Applications Conference (IEACon), 2016
Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Furt... more Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Further optimization in ion implantation process parameters is required in order to fabricate highly activated n-type junction in Ge. The co-implantation technique is one of interest due to the enhanced active carrier concentration attributed to the stress associated with atomic size of the non-dopant. In this work, phosphorus (P) and tin (Sn) have been selected as dopant and non-dopant atoms for the co-implantation process. Theoretical analysis on dopant distribution in the substrate was performed using TRIM software. The calculation predicted a maximum concentration of n-type dopant up to 1E20 cm−3. Fabricated samples were then experimentally analyzed using SIMS for depth profiling. A difference of less than one order of magnitude was observed from the comparison of both results. The difference between TRIM and SIMS is attributed to the sputtering effect and the rise of temperature during ...
2020 IEEE International Conference on Semiconductor Electronics (ICSE), 2020
One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with... more One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with high-mobility material of germanium. However, fabrication of Ge np junction faces low dopant activation problem due to the interaction between dopant and defect that was originated from ion implantation, during thermal annealing process results in dopant deactivation. Eventually, series resistance of np junction between source and drain regions will increase and affect the device drive current. Therefore, minimizing junction resistance remains an important issue to be solved. In this work, ultrafast/high temperature excimer laser of KrF was adopted for post-implantation annealing process in order to achieve high activation level. Laser energy fluences and shot numbers were varied between 100–2000 mJ/cm2 and 1–1000 shots, respectively to investigate the influence of laser parameter to the np junction resistance value, surface morphology and recrystallization. It is found that resistance ...
Journal of Materials Science: Materials in Electronics, 2021
The material cannot be used for any other purpose without further permission of the publisher and... more The material cannot be used for any other purpose without further permission of the publisher and is for private use only. There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.
The authors regret that the name of an important author, Dr. Zhongbiao Wu, who has contributed to... more The authors regret that the name of an important author, Dr. Zhongbiao Wu, who has contributed to this work was unintentionally omitted in the author list during the multi-institutional collaborations which involves intensive communications. Dr. Wu is the supervisor of Zhuxing Sun (the co-first author of this work) and has contributed significantly in drafting and revising this manuscript, and as such he should be included in the authorship.
IOP Conference Series: Materials Science and Engineering, 2017
Germanium (Ge) has re-emerged as a potential candidate to replace silicon (Si) as a substrate, du... more Germanium (Ge) has re-emerged as a potential candidate to replace silicon (Si) as a substrate, due to its higher carrier mobility properties that are the key point for the realization of devices high drive current. However, the fabrication process of Ge is confronted with many problems such as low dopant electrical activation and the utilization of heavy n-type dopant atoms during ion implantation. These problems result in more damage and defects that can affect dopant activation. This paper reports the electrical and structural analysis on the formation of ntype junction in Ge substrate by ion implantation, followed by excimer laser annealing (ELA) using KrF laser. ELA parameters such as laser fluences were varied from 100-2000 mJ/cm 2 and shot number between 1-1000 to obtain the optimized parameter of ELA with a high degree of damage and defect removal. Low resistance with a high degree of crystallinity is obtained for the samples annealed with less than five shot number. Higher shot number with high laser fluence, shows a high degree of ablation damage.
International Symposium on Electromagnetic Compatibility, Aug 21, 2000
The calculation of induced current on wires is important if equipment immunity to electromagnetic... more The calculation of induced current on wires is important if equipment immunity to electromagnetic hazards is to be assessed by numerical modelling. Differential techniques in the time domain are attractive for dealing with EMC calculations over a wide frequency range that involve complex geometries. This paper discusses the "in-cell" inductance and capacitance thin wire model currently used in the transmission line matrix (TLM) and finite difference time domain (FDTD) techniques. The performance of these models is assessed using some simple examples and comparison with method of moments calculations. It is concluded that care needs to be taken when using these models and the accuracy that can be obtained depends upon the proximity of the wires to conducting surfaces and other conductors.
Exceptional optical and electrical characteristics of graphene based materials attract significan... more Exceptional optical and electrical characteristics of graphene based materials attract significant interest of the researchers to develop sensing center of surface plasmon resonance (SPR) based sensors by graphene application. In this research carrier density variant in the form of conductance gradient on graphene based SPR sensor response is modeled. The molecular properties such as electro-negativity, molecular mass, effective group number and effective outer shell factor are engaged. In addition each factor effect in the cumulative carrier variation is explored analytically. The refractive index shift equation based on these factors is defined and related coefficients are proposed. Finally a semiempirical model for interpretation of changes in SPR curve is suggested and tested for some organic molecules.
Asia-Pacific Conference on Applied Electromagnetics, 2003. APACE 2003.
ABSTRACT Potentially differential methods in the time domain such as finite difference time domai... more ABSTRACT Potentially differential methods in the time domain such as finite difference time domain (FDTD) and transmission line matrix (TLM) are attractive for solving electrically large problems, as is often the case when carrying out computations for electromagnetic compatibility. FDTD algorithms that are second order accurate in time and space are inherently dispersive and anisotropic. This can potentially cause computational errors when considering electrically large problems. Using a fine mesh can reduce the numerical dispersion but significantly impacts on the computational resources required. FDTD schemes that are fourth order space and second order time significantly reduces the numerical dispersion with a minimal increase in computational requirements. Symmetrical condensed node TLM has also been used successfully to solve many electromagnetic problems. In this paper, a comparison is made for the dispersion in TLM, 2nd and 4th order FDTD when a Gaussian pulse is propagating in a WR90 waveguide. A waveguide was considered to be a good example to consider because the wave propagates at an angle to the axial direction that is frequency dependent. The results show that the TLM and 4th order FDTD exhibit significantly lower numerical dispersion than 2nd order FDTD, potentially making them suitable for the accurate solution of large scale EMC problems.
Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorp... more Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorption of biomolecule, is a way for SPR biosensor sensitivity enhancement. In this paper a graphene-based SPR biosensor with wavelength modulation will be presented. A few graphene layers added to a conventional gold thin film SPR biosensor leads to a drastic increase in sensitivity. This is due to the increased biomolecule adsorption in the graphene layers. In comparison to conventional SPR sensors this produces a large change in the index of refraction change at the metal-dielectric interface. In this paper, the reflection of light coupled into a SPR mode propagating along a thin Au-graphene layer surrounded by dielectric layers is simulated and it is compared with a conventional SPR sensor. The simulation of light reflection in wavelength modulation via MATLAB is illustrated.
There has been much recent interest in the application of plasmonics to improve the efficiency of... more There has been much recent interest in the application of plasmonics to improve the efficiency of silicon solar cells. In this paper we use finite difference time domain calculations to investigate the placement of hemispherical gold nanoparticles on the rear surface of a silicon solar cell. The results indicate that nanoparticles protruding into the silicon, rather than into air, have a larger scattering efficiency and diffuse scattering into the semiconductor. This finding could lead to improved light trapping within a thin silicon solar cell device.
A new class of three-component photocatalyst system is designed with plasmonic AuCu nanoprisms em... more A new class of three-component photocatalyst system is designed with plasmonic AuCu nanoprisms embedded between a porous single crystalline TiO 2 nanoplate thin film and dodecahedral zeolitic imidazolate frameworks (ZIF-8) nanoparticles for enhanced CO 2 photocatalytic reduction. The ZIF-8 plays a role of CO 2 capture to enhance the reactant concentration on the catalyst, while the AuCu nanoprism functions as an important mediator to improve the charge density at the interfaces and facilitate the charge transfer from TiO 2 to ZIF-8. The reactant CO 2 could be not only readily collected on the newly designed catalyst, but also more efficiently converted to CO and CH 4. As a result, compared to the reference sample of twocomponent system of TiO 2 and ZIF-8 with a CO 2 conversion rate of 12.5 µmol h-1. g-1 , the new three-component photocatalyst exhibited a nearly 7-fold improvement in CO 2 photocatalytic reduction performance with CO 2 conversion reaching an outstanding value of86.9 µmol h-1. g-1 , highlighting the importance of rational heterojunction design in facilitating reactant adsorption, charge transfer and reaction processes in photocatalysis.
New technological advancements in wireless networks have enlarged the number of connected devices... more New technological advancements in wireless networks have enlarged the number of connected devices. The unprecedented surge of data volume in wireless systems empowered by artificial intelligence (AI) opens up new horizons for providing ubiquitous data-driven intelligent services. Traditional cloudcentric machine learning (ML)-based services are implemented by centrally collecting datasets and training models. However, this conventional training technique encompasses two challenges: (i) high communication and energy cost and (ii) threatened data privacy. In this article, we introduce a comprehensive survey of the fundamentals and enabling technologies of federated learning (FL), a newly emerging technique coined to bring ML to the edge of wireless networks. Moreover, an extensive study is presented detailing various applications of FL in wireless networks and highlighting their challenges and limitations. The efficacy of FL is further explored with emerging prospective beyond fifth-generation (B5G) and sixth-generation (6G) communication systems. This survey aims to provide an overview of the state-ofthe-art FL applications in key wireless technologies that will serve as a foundation to establish a firm understanding of the topic. Lastly, we offer a road forward for future research directions. 1
Graphene possesses a high surface-to-volume ratio, which enables biomolecules to attach to it for... more Graphene possesses a high surface-to-volume ratio, which enables biomolecules to attach to it for bioelectronic applications. In this article, first, the classification and applications of bioelectronic devices are briefly reviewed. Then, recent work on real fabricated graphenebased bioelectronic devices as well as the analysis of their architecture and design using a computational approach to their charge transport properties are presented and discussed. A comparison to nongraphitic bioelectronic devices is also given. On the macroscale level, the design of devices is elaborated on the basis of a finite element analysis (FEA) approach, and the impact of design on the performance of the devices is discussed. On the nanoscale level, transport phenomena and their mechanisms for different design categories are elaborated on the basis of the density functional theory (DFT) and other quantum chemistry calculations. The calculated and measured charge transport properties of graphene-based bioelectronic devices are also compared with those of other available bioelectronic devices.
This study uses the combined visual and wireless information to make future wireless networks mor... more This study uses the combined visual and wireless information to make future wireless networks more reliable.
In this letter, we investigate the performance of reconfigurable intelligent surface (RIS)-assist... more In this letter, we investigate the performance of reconfigurable intelligent surface (RIS)-assisted communications, under the assumption of generalized Gaussian noise (GGN), over Rayleigh fading channels. Specifically, we consider an RIS, equipped with N reflecting elements, and derive a novel closedform expression for the symbol error rate (SER) of arbitrary modulation schemes. The usefulness of the derived new expression is that it can be used to capture the SER performance in the presence of special additive noise distributions such as Gamma, Laplacian, and Gaussian noise. These special cases are also considered and their associated asymptotic SER expressions are derived, and then employed to quantify the achievable diversity order of the system. The theoretical framework is corroborated by numerical results, which reveal that the shaping parameter of the GGN (α) has a negligible effect on the diversity order of RISassisted systems, particularly for large α values. Accordingly, the maximum achievable diversity order is determined by N. Index terms-Additive generalized Gaussian noise, error rate analysis, reconfigurable intelligent surfaces, Meijer's Gfunction. I. INTRODUCTION S MART radio environments, empowered by reconfigurable intelligent surfaces (RISs), are envisioned to revolutionize the design of wireless systems, since they offer the ability to control the propagation environment of electromagnetic waves through establishing desired channel responses. Unlike conventional transmission techniques, such as phased arrays, multi-antenna transmitters, and relays involving active components, RISs are composed of a large number of passive reflecting elements (REs), each is supported by the lowest number of small-sized, low-power, and inexpensive components [1]. With the aid of at least one smart controller, the amplitude and/or phase-shift of incident signals are manipulated at each RE in real time, allowing for a transformative control (i.e., scattering, reflection, absorption, and refraction) of the radio waves characteristics. To reap the full potentials brought by RIS and cater for their unique challenges, exploring the performance limits of RIS-assisted wireless communications analytically has become an active research topic [2]-[5]. Specifically, in [2], the error probability performance is investigated for RIS-assisted nonorthogonal multiple access (NOMA) and backscatter communication systems, respectively. Furthermore, [3] investigated the performance of RIS-assisted wireless systems, based on outage probability, symbol error rate, and ergodic capacity. Similarly, the ergodic capacity is studied in [4] for multipleantenna RIS-assisted systems. For two-way communications,
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