bluuebunny/crossref_metadata_2025 huggingface dataset:
Rare Earth Doped Lead Zirconate Titanate Thin Films for Memory and Power Device Applications
Authors: Bhattarai Mohan , Morell Gerardo , Katiyar Ram S.
Published: September 2023

We fabricated thin films of (PbZr0.53Ti0.47)O3 (PZT) and (PbZr0.53Ti0.47)0.90(LaxSc1-x)0.10O3 where; x= 0, 0.2, 0.4, 0.6 and 0.8 denoted as [abbr. PL10x] PL0, PL2, PL4, PL6, and PL8 respectively on the LSMO buffer layer (bottom electrode) by using a PLD technique. The X-ray diffraction peaks show a single-phase perovskite structure of thin films with a preferred (100) orientation that coincides with the MgO and has tetragonal phase symmetry (P4mm). Pt electrodes were deposited at the top of thin films as top electrodes. We achieved higher dielectric permittivity (ε’) for PL0 and PL6 compared to other compositions. We noticed that the role of increasing lanthanum content (decreasing scandium) resulted in the broadening of ε’ with temperature and ferroelectric phase transition decreased to 450 K. However, the scandium doping alone (PL0) didn’t lower the ferroelectric phase transition. We analyzed the temperature-dependent ε’ using the modified Curie-Weiss law. The PL0, PL6, and PL8 thin film capacitors exhibited relaxor ferroelectric properties that were further supported by the Vogel-Fulcher relation.

The P-E hysteresis loops exhibited the role of lanthanum and scandium causing compositional changes in coercive fields. The P-E loops of PZT, PL2, and PL4 exhibited typical ferroelectric features. Whereas, PL0, PL6, and PL8 showed a relaxor ferroelectric behavior which was corroborated by the analysis of the dielectric data. The PL0 and PL6 thin films showed better spontaneous polarization Ps. We achieved superior energy storage performance Ure = 54.63 J/cm3 with η ~ 70% for PL0 and Ure = 26.54 J/cm3 with η ~ 66% for PL8 thin film capacitors. The study demonstrated the idea that by tuning La3+ and Sc3+ the dielectric and ferroelectric properties of thin films can be controlled for suitable electronic applications, such as memory, power devices, and energy storage.
(Invited) Universal Alignment of Surface and Bulk Oxygen Levels in Semiconductors
Authors: Chakrapani Vidhya
Published: September 2023

Lattices of most semiconductors have a large density of intrinsic and extrinsic defects which gives rise to effects such as surface Fermi level (EF) pinning, dopant compensation, asymmetrical p versus n-doping, and device degradation. Oxygen and hydrogen are the two most important impurities in semiconductors because of their ubiquitous presence in growth and device processing environments and consequently their incorporation strongly influences electronic and electrical properties. Therefore, a deeper understanding of the interaction of these species with the semiconductor surface and bulk defects is necessary for enabling the development of devices based on them such as photovoltaic and photocatalytic systems, fuel cells, and many others. Analysis of the reported surface work function values and the substitutional bulk O-defect energies show that the surface Fermi level of position in a broad range of group IV, III-V, II-VI, and I-III-VI2 semiconductors with physisorbed O2 lies universally at approximately -5.1 eV below the vacuum level. Similarly, results show that the energy of the bulk substitutional O-related amphoteric defects incorporated during crystal growth also has a universal energy of ~ -5.0 eV with respect to the vacuum level for most of the investigated semiconductors. It is shown that the process of ‘surface transfer doping’ that involves an adsorbed nanoscale water film on the semiconductor surface is likely responsible for the universal alignment of oxygen levels.

Figure 1
(Invited) Doping of Aluminum Gallium Oxide Alloys
Authors: Wickramaratne Darshana
Published: September 2023

Designs of electronic devices using aluminum gallium oxide (ALGO) alloys as the barrier layer and gallium oxide (Ga2O3) as the active layer are being considered. The success of these devices is predicated in part on the ability to achieve controlled doping of the ALGO barrier layer. First-principles calculations using hybrid functionals can be instrumental in guiding this effort. I will highlight which dopants can lead to controlled doping in high-Al content ALGO alloys, identify the optimal doping conditions and discuss the impact of the different ALGO polymorphs on this effort.

This work was performed in collaboration with J.B.Varley and J.L. Lyons and was supported by the ONR/NRL 6.1 Basic Research Program.
Determination of Type II Band Alignment of NiO/α-Ga2O3 For Annealing Temperatures Up To 600°C
Authors: Xia Xinyi , Li Jian-Sian , Chiang Chao-Ching , Yoo Timothy Jinsoo , Hershkovitz Eitan , Ren Fan , Kim Honggyu , Kim Jihyun , Jeon Dae-Woo , Park Ji-Hyeon , Pearton Stephen J
Published: September 2023

There is increasing interest in the alpha polytype of Ga2O3 because of its even larger bandgap than the more studied beta polytype, but in common with the latter, there is no viable p-type doping technology. One option is to use p-type oxides to realize heterojunctions and NiO is one of the candidate oxides. The band alignment of sputtered NiO on α-Ga2O3 remains type II, staggered gap for annealing temperatures up to 600 °C, showing that this is a viable approach for hole injection in power electronic devices based on the alpha polytype of Ga2O3. The magnitude of both the conduction and valence band offsets increases with temperature up to 500 °C, but then is stable to 600 °C. For the as-deposited NiO/α-Ga2O3 heterojunction, ΔEV = −2.8 and ΔEC = 1.6 eV, while after 600 °C annealing the corresponding values are ΔEV = −4.4 and ΔEC = 3.02 eV. These values are 1−2 eV larger than for the NiO/β-Ga2O3 heterojunction.

Figure 1
Selective Wet and Dry Etching of NiO over β-Ga2O3
Authors: Chiang Chao-Ching , Xia Xinyi , Li Jian-Sian , Ren Fan , Pearton Stephen J
Published: September 2023

In this study, a reaction-limited chemical wet etching process of NiO by an HNO3-based solution, with a complete selectivity over β-Ga2O3 was investigated. The threshold ion energies for inductively coupled plasmas (ICP) dry etching of NiO in BCl3 discharges, its selectivity to β-Ga2O3, and the cleaning effect for chlorine-based residues remaining on the surface after plasma exposure was also examined. One of the major drawbacks of β-Ga2O3 device design is the lack of p-type dopants. An alternative approach is to use a p-type oxide, NiO, to form heterojunctions with n-type Ga2O3. Therefore, a selective wet and dry etching process development is in demand for the optimized pattern transfer process. A solution of 1 HNO3: 4 H2O exhibited measurable etch rates for NiO above 40°C and wet etching activation energy of 172.9 kJ.mol-1 (41.3 kCal.mol-1, 1.8 eV/atom), which is firmly in the reaction-limited regime. The selectivity over β-Ga2O3 was infinite for temperatures up to 55 °C. The strong negative enthalpy for producing the etch product Ga(OH)4 suggests that HNO3-based wet etching of NiO occurs via the formation and dissolution of hydroxides. The BCl3/Ar ICP etching produced maximum etch rates up to 300 Å.min-1 for NiO and 800 Å.min-1 for β-Ga2O3 under moderate plasma power conditions. The selectivity for NiO: Ga2O3 was < 1 under all conditions. The ion energy threshold for the initiation of etching NiO was between 35-60 eV, depending on the plasma power conditions. And its etching mechanism was ion-driven, as determined by the linear dependence between etch rate and the square root of ion energy incident on the surface. By sharp contrast, the etching of Ga2O3 had a stronger chemical component without a well-defined ion energy threshold. After being exposed to BCl3 plasmas, both NiO and Ga2O3 surfaces show chlorine residues, which can both be removed by the standard 1NH4OH: 10H2O or 1HCl: 10H2O solution used for native oxide removal. In addition, according to the location of the Cl 2p3/2 peak in the XPS analysis on the surface, the chlorine particles were ionically bonded.

Figure 1
(Invited) Extraction of Trap Level in GaN Hemt from Transient Current upon Back Gate Voltage Application
Authors: Nishida Kisara , Hoshii Takuya , Wakabayashi Hitoshi , Tsutsui Kazuo , Kakushima Kuniyuki
Published: September 2023

Gallium nitride (GaN) have attracted attention as a high frequency and high voltage power device material because they have wide bandgap and high mobility [1]. However, large number of defects exists in the epitaxial layer. Current collapse originated from the traps at the surface and in the buffer layer is one of the results of the defects [2]. To distinguish the bulk traps from the whole current collapse, back-gate voltage application is commonly used [3]. In this study, we measured the bulk traps by measuring the drain transient current by back gate voltage application.

TLM pattern (L/W=120/100 mm) was fabricated on an epitaxial wafer; GaN(2nm)/AlGaN(26nm)/ GaN(150/350nm)/C-GaN/buffer/Si sub. Fig. 1 shows the I
d-V
B characteristic of the TLM, where a threshold voltage (V
th) of -300/-450 V can be extracted. A large clock-wise hysteresis suggests large amount of electron trapping in the epitaxial layer. Fig. 2(a) shows the voltage application sequence for measuring the transient I
d 2DEG current. A negatively high V
B below the V
th was applied to clear all the traps initially exists in the epitaxial layers. Then, a step voltage was applied to a certain voltage, and the transient I
d was monitored until the value saturates. Fig. 2(b) shows typical transient I
d on V
B. To analyze the time constant (t) of the transient, the differential of the I
d on logarithm time was used, as the time at the peak signal corresponds to the time constant. Fig. 3(a) shows analysis result, and the peak of this graph correspond to t. On the other hand, the amplitude is related to trap density. Fig. 3(b) shows the Alenius plot of the extracted t, and activation energy from 0.2 to 0.3 eV was detected.

In conclusion, we have measured the transient I
d of GaN-HEMT device with a step voltage application to the substrate back gate. From analysis, we extracted defect levels with activation energy of 0.2 to 0.3 eV. The method is useful for characterizing the trap density in the epitaxial layers.

[1] T. Mizutani, et al., IEEE Trans Electron Devices,
50, 10, 2015 (2003).

[2] G. Meneghesso, et al., IEEE Trans Electron Devices, 53, 12, 2932 (2006).

[3] X. Chen, et al., Appl. Phys. Lett.,
117, 26, 263501 (2020).

Figure 1
(Invited) New Layout Styles to Boost the Electrical, Energy, and Frequency Response Performances of Analog MOSFETs, Considering a Wide Range of High Temperatures
Authors: Gimenez Salvador Pinillos , Galembeck Egon Henrique Salerno
Published: September 2023

The 1st generation of innovative gate layout styles for MOSFETs have proven to be able to enhance the electrical performance and tolerance to ionizing radiation of analog MOSFETs. This paper presents the 2nd one. It preserves the new effects of the 1st generation and is able to further reduce the Leff of MOSFETs in relation to those achieved by the 1st generation, considering a wide range of high temperatures. We observe that the Half-Diamond layout style is able to boost the saturation drain current and the unity voltage gain frequency by up to 52.4% and 75%, respectively. Therefore, this technique remains an alternative to improve the electrical performance of analog MOSFETs, mainly for space, nuclear and medical CMOS ICs applications.

Figure 1
(Invited) implantable and Bioresorbable Chemical Sensors for in-Vivo Real-Time Tracking of Analytes of Clinical Interest
Authors: Barillaro Giuseppe
Published: September 2023

Imagine your doctor could slip a miniaturized sensing system under your skin and use it to continuously monitor the concentration of almost any molecule in real-time as it circulates through your peripheral blood. This would revolutionize many areas of diagnostics, enabling individualized reports on both disease progression and drug efficacy to be achieved continuously, in real-time. Imagine the sensing system implanted under your skin to communicate with your mobile phone (wireless communication) to transfer the clinically relevant data (biomarker or drug concentration) directly to your doctor. This would impact the way we diagnose diseases and monitor drug efficacy, currently based on single-moment-in-time tests, enabling personal, timely, and effective medical feedback (real-time personalized medicine). Finally, imagine the biochemical sensor in your body is resorbed upon a click, once you don’t need it anymore. This would eliminate any need for sensor retrieval, avoiding risks connected to surgery and providing a risk-free “red button” to destroy it, in case issues will occur (e.g., end of the therapeutic process, inflammation, malfunctioning).

In this lecture, cutting-edge research on the use of bioresorbable nanostructured materials for the development of implantable bioresorbable sensors for analytes of clinical interest (e.g., drugs, biomarkers, ions) in-vivo, in-situ, and in real time that completely dissolve with biologically benign by-products after use will be will reviewed and discussed.

References

A. Paghi, Corsi, A. A. La Mattina, G. Egri, L. Dähne, and G. Barillaro, Wireless and Flexible Optoelectronic System for In-Situ Monitoring of Vaginal pH Using a Bioresorbable Fluorescence Sensor, Advanced Materials Technologies (2022)

M. Corsi, A. Paghi, S. Mariani, G. Golinelli, A. Debrassi, G. Egri, G. Leo, E. Vandini, A. Vilella, L. Dähne, D. Giuliani, and G. Barillaro, Bioresorbable Nanostructured Chemical Sensor for Monitoring of pH Level In Vivo, Advanced Science
, 2202062 (2022). DOI: 10.1002/advs.202202062.

A. A. La Mattina, S. Mariani, G. Barillaro, Bioresorbable Materials on the Rise: From Electronic Components and Physical Sensors to In Vivo Monitoring Systems, Advanced Science, 1902872 (2020). DOI: 10.1002/advs.201902872
Development of a Self-Powered Microneedle Based Wearable Electrochemical Sensor for Glucose Monitoring
Authors: Ganguly Anindita , Chung Jun-Hsuan , Fan Kai Po , Liu Kuei-Lin , Sharma Manish Kumar , Lin Zong-Hong
Published: September 2023

Diabetes is increasingly being recognized as a worldwide public health concern owing to the affected rate of the patients in the past years. One of the major barriers to the disease control is the lack of sensitive and reliable point-of-care device that can provide quantitative diagnosis and monitoring. The wearable sensing technology has the potential of revolutionizing the precision medicine and personalized healthcare system. Within the emerging class of wearables, the microneedle-based sensors play a key role in combining the advantages of monitoring the analytes in interstitial fluid (ISF) and minimally invasive skin pricking. However, such devices require appropriate power sources to realize their full capacity, and the increasing power costs, global warming, and environmental pollution are certain aspects that needs to be pondered upon. Researches are dedicated on power generators with focus on wearable energy harvesters to address the issue of power supply. Thermoelectric generators (TEGs) have the ability to generate power by transforming thermal energy to electrical power output. Herein, we have developed a microneedle based enzymatic, electrochemical glucose sensing system powered by TEG utilizing the body heat. 1 mm stainless steel microneedles were sputtered with gold and platinum, and further coated with graphene paste, glucose oxidase, poly-hydroxyethyl methacrylate, and nafion. The fabricated device exhibited a good sensitivity, and a wide linear range. According to the World Health Organization (WHO), the normal glucose level in human body are between 4.0 mM to 5.6 mM, and our device has shown a concentration dependent output current signal from 4.0 mM to 24.0 mM. The device has also exhibited excellent detection results in real-sample (artificial ISF) in vitro study as well as in vivo analysis performed in 12 – 15 weeks SD rats. The device is completely self-powered where the TEG derives power from the temperature gradient between the body heat and the exposed environment. The novelty of this work lies in integrating the microneedle-based sensing device with the TEG as the power source. The results indicate a promising self-powered sensor with the renewable and sustainable source of power ensuring continuous operation.
A Self-Powered Microfluidic-Based Flexible Triboelectric Sensor for Noninvasive Sweat Analysis
Authors: Peringeth Kiran , Ganguly Anindita , Chatterjee Subhodeep , Lin Zong-Hong
Published: September 2023

Sweat, an abundant biofluid containing rich source of physiological and metabolic information regarding the health of an individual, with the potential for noninvasive extraction. Health monitoring via quantitative sweat analysis could potentially preclude the need for periodic blood sample assessments. Continuous monitoring of key electrolytes such as sodium can provide a wide range of information from electrolyte imbalance to diagnosis of cystic fibrosis. This makes the quantification of sodium ions important since the loss of sodium could lead to hyponatremia. About 5% of the adults and about 35% of hospitalized patients suffer from hyponatremia which makes it one of the most common electrolyte disorder. Therefore, developing a robust sensing platform is indispensable. A flexible, thin class of microfluidic device has been introduced of late, that can be used for sweat extraction and quantifiable monitoring of the sweat analytes. However, these devices operate with high cost, complex design, and an active power source. Therefore, in our study, we address such challenges by developing a triboelectric nanogenerator (TENG) based self-powered microfluidic device that works on contact electrification. The wearable microfluidic device monitors the sodium levels in the sweat of the individual extracted in a non-invasive manner. The flexible microfluidic channel utilizes the capillary action generated with the periodic finger tapping to transport the sweat from skin to the sensing area. The transported sweat is used in the liquid - solid interaction between the sweat and microfluidic channels with electrode coated with ion selective membrane (ISM) to obtain triboelectric output. The ISM coating on the electrode is able to selectively detect the target analyte which results in a significant difference in output. This study demonstrates a flexible microfluidic based self-powered noninvasive sweat sensor which has potential applications in analysis of electrolyte loss through sweat.
Wearable Foot Pressure Sensing System for Fallen Arch Analysis
Authors: Tseng Yao-Hsuan , Lin Zong-Hong
Published: September 2023

The main purpose of this research is to distinguish the extent of fallen arch by analyzing the center of foot pressure when people are walking. Fallen arch is often called the flatfoot. There are two types of flatfoot, the rigid flatfoot and the acquired flatfoot. The rigid flatfoot is because of bones formation, and people often get rigid flatfoot when they are young. The acquired flatfoot occurs usually on adults because of the walking postures, shoe types, weight and so on. Since these reasons, it is possible that we can improve or prevent the acquired flatfoot through wearing orthotic insoles or changing the walking posture. That’s the reason why our research is focusing on the acquired flatfoot. In this research, we develop a wearable foot pressure sensing system, consist of wireless Bluetooth transmit module and sensing insoles. The wireless Bluetooth transmit module helps to accomplish our measuring system as a wearable device. The sampling rate of wireless Bluetooth transmit module is one thousand samples per second. As a result, we can get a very detailed track on the walking motions. The sensing insoles are made of triboelectric nanogenerator (TENG) technology. The working principle of TENG is based on the coupling of triboelectric effect and electrostatic induction. Depending on the property of triboelectric generation of different materials and through continuous contact and separation, there is an electrostatic induction and current flow between the triboelectric layers and the electrodes, thus causing the potential difference. By detecting the potential differences, we can get the signals of pressure, so we can calculate the center of foot pressure and compare with the standard to check which walking posture we can apply to improve the fallen arch and find out where the center of foot pressure should be placed. Using this system, we can get the real-time foot pressure information and collect the information anytime and anywhere, accomplishing the smart medical.
(Invited) self-Powered Multifunctional Sensing and Control for Smart Wearables and Human-Machine Interfaces
Authors: Cao Changyong Chase
Published: September 2023

Robust, high-performance tactile sensors are critical for developing soft intelligent robotics, human-machine interfaces (HMI), and wearable electronics. However, it is challenging to fabricate soft tactile sensors capable of multifunctional sensing under both fast and slow response conditions in a simple and low-cost manner. In this talk, I will present our recent efforts in developing novel self-powered sensors and HMIs for wearables and intelligent controls. I will first introduce a textile-based tactile sensor capable of multifunctional sensing (covering both dynamic and static measurements) for personalized healthcare monitoring and soft robotic control. Inspired by human skin, the tactile sensor consists of a triboelectric nanogenerator sensing layer to mimic the function of fast-adapting (FA) mechanoreceptors and a piezoresistive sensing layer to achieve the functionality of slow-adapting (SA) mechanoreceptors. Then, I will demonstrate a self-powered breath sensor to monitor the health conditions of patients and provide daily assistance for severely disabled people to control electrical household appliances and other smart systems. The new system provides the advantages of high sensitivity, good stability, low cost, and ease of use.
Acinetobacter Baumannii Detection Using A Bio-FET Device: Towards Healthcare Infection Management
Authors: Cheng John ChauFu
Published: September 2023

Acinetobacter is a group of bacteria commonly found in the environment, like in soil and water. While there are many types, the most common cause of infections is Acinetobacter baumannii, which accounts for most Acinetobacter infections in humans.

Acinetobacter baumannii could result in infections in the blood, urinary tract, in wounds of the body or lungs. Traditionally, medical technicians in hospital use the sample from patients (like stool, urine, or sputum) to streak on a plate or do bacteria culture test. It takes too much time and patients cannot wait so long. Therefore, it is vital that a new diagnostic technique can be used to detect Acinetobacter baumannii much faster than the traditional methods.

The electrical double layer (EDL)-gated field-effect transistor-based biosensor (BioFET) is a fast and promising diagnostic technique because it is highly sensitive, quickly response, and high selective to the target analyte. Besides, a portable device could help the medical personnel detect the bacteria and treat the patients as early as possible. Here, we used a portable BioFET device from STARX co. (Model II) to detect the complementary Deoxyribonucleic acid (DNA) of Acinetobacter Baumannii via a specific DNA probe we designed. We utilized the portable device to examine the specificity and selectivity in various conditions, such as urine and blood. Thus, the results showed that the system with the portable device could give the hospital personnel a tool to control healthcare associated infection caused by Acinetobacter baumannii.

Figure 1
Surface-Enhanced Raman Spectroscopy Combined with External Electric Fields for Non-Invasive Glucose Sensing
Authors: Liu Kuei-Lin , Lin Zong-Hong , Fan Kai Po
Published: September 2023

Blood glucose detection has been a critical issue in the medical field all over the world for a long time. Especially for diabetic patients, regular monitoring of blood glucose is necessary in their daily life. Nowadays, blood glucose detection mainly relies on fingertip blood glucose meters, which can provide the current blood glucose level in a short period of time. Meanwhile, there are several inconveniences and concerns, including the pain and discomfort of needle-prick blood collection, and the risk of infection at the needle-prick wound. Therefore, many researchers have devoted themselves to the development of non-invasive glucose detection in recent years. Till now, the practical glucose measurement in vivo is still faced with lots of difficulties. To get the signal or response of the molecules in vivo without penetration through the skin layers required two main properties. First of all, the biologic blockage and noise need to be avoided or overcame during the detection. Secondly, it’s necessary to enhance or amplify the signal due to relative low concentration of the target molecule under the skin. Here we introduce a surface-enhanced Raman spectroscopy (SERS) combined with external electric fields to achieve the goal of the detection in vivo without any invasive procedure. In the SERS system, we select 785 nm laser to reach deeper area through the skin layers while preventing the heat effect for tissue damaging. Next, with the signal differences from encountered with various concentration of glucose, 4-mercaptophenylboronic acid (4-MPBA) on silver nanoparticles (AgNPs) is able to quantify the glucose concentrations from the characteristic peak of the Raman shift. Furthermore, the combination with external electric fields induces coagulation of the sensing nanoparticles and provides many hotspots for SERS detection in vivo. We believed that this work is a great stepping stone of real time non-invasive glucose sensing in practical application.
(Invited) a Dynamically Reprogrammable Surface with Self-Evolving Shape Morphing
Authors: Bai Yun , Wang Heling , Huang Yonggang , Rogers John , Ni Xiaoyue
Published: September 2023

Shape-morphing soft materials are ubiquitous in living systems. They are of increasing relevance to emerging technologies in soft machines, flexible electronics, and smart medicine. The past decade has witnessed phenomenal investment in developing active materials that can shift their shapes, and henceforth their performing functions. However, creating schemes to swiftly reprogram target shapes after fabrication remains challenging. Complexities associated with the operating physics and disturbances from the environment can stop the use of deterministic theoretical models to guide inverse design and control strategies. In this work, we describe a dynamically reprogrammable metasurface with embedded actuation, sensing, and feedback control. The voltage-controlled electromagnetic force drives a flexible, conductive 2D mesh into a diverse set of complex 3D surfaces in the presence of a static magnetic field. The unusual construction of the metasurface from a matrix of filamentary metal traces enables the system to adopt an approximately linear model for inverse design. Implementing an in-situ stereo-imaging feedback strategy with a digitally controlled actuation scheme guided by an optimization algorithm yields surfaces that can morph into target shapes without any presuming models. The closed-loop self-evolving inverse design approach opens opportunities for physical simulations for non-linear or non-ideal systems.
(Invited) Development of Cell-Based Biosensor Platform for Monitoring the Effect of Functional Nanocarriers As Drug Delivery System on Breast Cancer Cells
Authors: Lin Shu-Ping
Published: September 2023

With the rapid emerging research of nanotechnology and engineering in biomedical applications, scientists start to develop state-of-the-art diverse biosensing platforms. Here, in-vitro cell-based biosensor (CBB) was fabricated using nano/micro technologies to electrophysiologically observe the effects of drug treatment on human breast cancer cells. Indium tin oxide coated vertically aligned silicon nanowires (ITO-coated VA-SiNWs) were applied as a cell monitoring CBB platform to investigate the growth and adhesion of MCF-7 human breast cancer cells via impedimetric method. Monitoring was performed by measuring the non-Faradaic electrical impedance of the cell–APTMS-modified ITO-coated VA-SiNWs system using a precision LCR meter. Our APTMS-modified ITO-coated VA-SiNWs exhibited changes in impedance parameters during cell growth. It was observed that during MCF-7 cell growth, the impedance magnitude increased. By contrast, the cytolysis of the cells led to significant changes in impedance parameters. Impedimetric cell monitoring platform has the ability to observe MCF-7 cell growth and adhesion and investigate anomalous and non-electrogenic cell behavior in toxin and drug screenings. With the aid of CBB platform, the real-time electrical signals can be applied to monitor the therapeutic efficacy of the nanocarriers in drug delivery system and screening large libraries of potential drugs for cancer treatment. Moreover, our pilot study indicates that our CBB could be a feasible platform to reduce/replace the use of animals based on the “Three R principles” in animal-based research in the future.

Figure 1
The Contact Electrification Capability of Amino Acids
Authors: PAL Arnab , Ganguly Anindita , Lin Zong-Hong
Published: September 2023

Triboelectric charging necessitates a frictional contact between two different materials, and contact electrification is typically based on the polarity difference in the triboelectric series. The human skin is a prominent triboelectric material that becomes highly positive during the contact electrification process. However, the reason behind this phenomenon is still remains unrevealed. Herein, we have performed an in-depth analysis of the amino acids present in human skin and quantifying them with regards to triboelectric polarization. The principle focus of this study is based on analyzing those amino acids present in copious amounts in the human skin. The phenomenon of contact electrification is in close relation to the work function and the electron-donating or accepting ability of the material. The standardized experimental as well as computational approaches were employed to analyze the amino acids. Thus, we present an augmented triboelectric series of the amino acids with quantified triboelectric charging polarity by scrutinizing the triboelectric transfer charge, work function, and electron binding energy. Furthermore, a comparison of these properties in the amino acids predominant in the human skin can conclusively render it positive in the series, under contact electrification. The quantification of the triboelectric series may serve as a benchmark for implementing in various applications in the future such as self-powered sensing, or energy harvesting.
Development of Label-Free Triboelectric Nanosensor as a Drug Screening Platform
Authors: Cheng Yu-Ying , Lin Yu-Zih , Pal Arnab
Published: September 2023

Due to the emergence of new diseases, drug resistance and other factors, the discovery and development of new drugs has always been a very important issue in our life. However, discovering and developing new drug requires extensive pharmacological assessment, which is a complex, prolonged, highly expensive and risky process and takes about 10 to 15 years for the drug to be clinically approved. Recently, in order to improve the efficiency and accuracy of drug development, the researchers have been working on developing new drug screening platform. This research is dedicated to the development a label-free, rapid, easy operation and cost-efficient drug screening platform based on triboelectrification. Triboelectrification, also known as contact electrification, is the phenomenon which occurs when two interfaces come into contact and causes charge transfer between them. Recently, new technology with high development potential based on triboelectrification is called triboelectric nanogenerator (TENG), which can transfer mechanical energy into electrical energy. Moreover, TENG is developed as a self-powered sensor called as triboelectric nanosensor (TENS), which is coupling TENG and sensor. This work is the first drug screening platform of its kind based on triboelectrification. Recently, TENS have been developed for chemical sensing applications, in which the contact interface of TENG is functionalized with probe molecules with selectivity for different chemical analytes. After functionalization of the triboelectric contact layer, the rate of electron transfer induced by the triboelectric effect is different, result in the change in the electrical signal of TENG. When the contact interface is modified with target analyte, we observe a variation in the measured electrical output signal due to the amount of target on contact interface, thus demonstrating a self-power sensing process without any external power source. Here, we propose a new platform which when functionalized with protein, exhibits a variation in the electrical output signal with different concentration of drug. Furthermore, based on triboelectric effect, the as-prepared sensor was used to detect drug molecules with different binding affinities to the probe protein. The obtained results demonstrate a great potential for a highly sensitive drug screening platform.
(Invited) hybrid Nanomanufacturing of Self-Powered Human-Integrated Sensors
Authors: Wu Wenzhuo
Published: September 2023

The seamless and adaptive interactions between functional devices and their environment (e.g., the human body) are critical for advancing emerging technologies, e.g., wearable devices, consumer electronics, and human-machine interface. The state-of-the-art technologies, however, require a complex integration of heterogeneous components to interface the mechanical stimulus which is ubiquitous and abundant in the above applications. These limitations have severely hampered the advancement and broader utilization of related technologies. Moreover, all existing technologies require a power source, which complicates the system design and limits operation schemes.

In this talk, I will discuss our recent progress in developing self-powered human-integrated sensors through the hybrid nanomanufacturing of heterostructured devices. This new class of wearable devices are conformable to human skins and can sustainably perform self-powered, non-invasive functions, e.g., physiological monitoring and gesture recognition, by harvesting the operation power from the human body. This research is expected to have a positive impact and immediate relevance to many societally pervasive areas, e.g., telehealth, consumer electronics, and robotics.
(Invited) Air-Permeable MXene Electrode with Miura-ori Structure for Biosensing
Authors: Lin Tzu-En , Tsai Chih-Ning , Yang Pei-Wen , Huang Chih-Ching
Published: September 2023

MXene is a two-dimensional nanomaterial composed of transition metal carbides/nitrides/carbonitrides developed in recent years. The general formula of MXene is Mn+1XnTx, where X is C or N, M is a transition metal, n is between 1 and 3, and Tx represents different functional groups on the surface. Currently, a popular method for preparing MXene is MAX phase selective etching of A-layer atoms. It has often been used as an useful materials for sensors or as biosensors due to its outstanding physical-mechanical properties, excellent electrical conductivity, and nanostructure to improve the sensitivity, conductivity, and catalytic performance of the sensing devices. In this work, we present an air-permeable MXene electrode capable of recording electromyographic (EMG) signals on the skin surface based on Miura-ori structure. Taking advantages of the Miura-ori structure, MXene-based electrodes have high breathability and low and stable electrode-skin interfacial impedances, facilitating long-term reliable electrophysiological monitoring. The electrolytic gel on top of the conventional wet Ag/AgCl gel electrodes increases the impedance between the electrode and the skin as it gradually dries, inhibiting sweat evaporation and affecting signal acquisition. Therefore, we provide a fascinating electrode design that can be used to obtain high-quality sEMG signals for evaluating body movements such as swallowing.
(Invited) Non-Enzymatic Glucose Sensor Fabricated By Ni-Nanowires Decorated Graphene Gated FETs
Authors: Hung Sheng-Chun , Chen Chia-Chi , Lin Yu-Cheng , Lin Chung-Wei
Published: September 2023

In this study, an innovative non-invasive glucose sensor made of nickel nanowire-decorated graphene-gated field-effect transistors is demonstrated. Due to the redox reaction between nickel nanowires and glucose molecules in weakly alkaline solution, electron exchange occurs when Ni(III) reacts with glucose to form Ni(II) and gluconolactone. In order to improve the sensitivity of the glucose sensor and reduce the detection limit, we compared the characteristics of the glucose sensor fabricated by nickel nanowires on gold surface and graphene/gold surface, respectively. Since the CVD-grown graphene film has excellent electrical conductivity and no defects, the electrons generated by the redox reaction can be quickly and evenly dispersed and are not easily neutralized, resulting in a change on the gate potential, thereby affecting the current between the source and the drain metal, and then the glucose concentration in the solution can be deduced. It can be seen from the experiments that the glucose sensor with graphene film has better current stability, lower detection limit and better linear relationship between current and concentration. The demonstrated nickel wire-decorated graphene-gated FET biosensor can be used for the quantification of glucose with a linear range of 10-50 mM and a detection limit of 51nM.

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(Invited) wearable Hydrogel Patch with Noninvasive, Electrochemical Glucose Sensor for Natural Sweat Detection
Authors: Li Bor-Ran
Published: September 2023

Recent advances in microelectronics and electrochemical sensing platforms have preceded the development of devices for personal monitoring and managing physiological and metabolic information that exploit sweat as a noninvasive, convenient approach for providing information about underlying health conditions, such as glucose level monitoring. Although most sweat glucose sensors have targeted applications during exercise and other active stimulation induced-sweat, natural sweating offers an attractive alternative with minimal effect on users that can be accessed during routine and sedentary activities without impeding personal lifestyle and preserves the correlation between blood and sweat glucose. Here, we present a noninvasive sweat glucose sensor with convenient hydrogel patches for rapid sampling of natural perspiration without external activities that stimulate sweating. The wearable hydrogel patch rapidly takes up natural sweat from the hand and serves as a medium for electrochemical sensing. A prussian blue-doped poly(3,4-ethylenedioxythiophene nanocomposite (PB-PEDOT NC) electrode provides cost-effective, stable and excellent electrocatalytic activity in sweat glucose measurements. We demonstrated sweat glucose sensor functionality by long-term measurements of glucose in sweat from human subjects consuming food and drinks. By enabling the analysis of sweat glucose during routine and sedentary activities, the sweat glucose sensor shows great promise for clinical-grade glucose management and enlarges the scope of next-generation noninvasive sensing systems.
Fabrication of Aptamer-based Field Effect Transistor Sensors for Detecting Mercury Ions
Authors: Wang Yu-Lin , Zeng Guan-Cheng , Lee Chun-Ta , Lin Chia Kai , Kuo Tzu-Han , Paulose Akhil K , Lin Zong-Hong , Hung Sheng-Chun
Published: September 2023

With the rapid development of industry, the pollution of the environment is becoming more and more serious. Among them, water pollution is one of the most serious problems, and polluted water sources often contain heavy metal ions such as mercury, chromium, lead, chromium, arsenic, etc. Which in turn affect our irrigation, breeding, food, and drinking, and finally cause physical harm. Mercury is still widely used today. For example, mercury and mercury compounds are used as catalysts in the plastics industry. Mercury is still widely used today. For example, mercury and mercury compounds are used as catalysts in the plastics industry. Some toxic pesticides also contain mercury. Mercury is used in daily life in fluorescent lamps, batteries, thermometers, medical amalgams, etc.

Mercury pollution can be divided into two categories: organic mercury and inorganic mercury. Prolonged exposure to mercury can cause paralysis and a progressive loss of sense of touch, sight, hearing, or taste. Other more common neurological symptoms include memory and balance impairment, insomnia, hand tremors, and behavioral disturbances. Detecting the mercury content in water usually requires large-scale laboratory instruments for measurement, costing a lot of money and time.

In this study, a specific aptamer is combined with a field-effect transistor to form an aptamer field-effect transistor by utilizing the properties of thymine-Hg(II)-thymine (T-Hg(II)-T) coordination chemical bonds. A highly selective and sensitive mercury ion sensor was achieved by using N-channel depletion-mode MOSFETs with APTAMER-modified gates. For the Aptamer-modified FET sensor, a detection limit of 0.2 PPM was achieved using a 500 μM × 500 μM gate sensing area. Biosensors realize reduced size, shorter detection speeds, cost savings, and high detection of limit sensors. Therefore, the determination of heavy metal ions in the environment by simple and easy-to-use instruments is of great significance for disease prevention.

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The Impact of Cation Contamination on Proton Exchange Membrane Water Electrolyzer (PEMWE)
Authors: Sun Qiang , Yang Fan , Jia Qingying , Mittelsteadt Cortney
Published: September 2023

Hydrogen has emerged as a promising clean energy carrier and source alternative to fossil fuels(1). Mass production of cost-effective hydrogen without pollution is essential for the so-called hydrogen economy and the hydrogen produced in this process is called green hydrogen(2). It uses renewable energy such as wind energy and solar energy to generate electricity and produce hydrogen via water electrolysis, with net-zero carbon emissions. The proton exchange membrane water electrolyzer (PEMWE) is one of the most commercially available devices for water electrolysis. A membrane electrode assembly (MEA), which is laminated from an anode, cathode, and proton exchange membrane, is prone to poor performance and low lifetime if exposed to cation contamination due to the chemical properties of the materials, such as the negatively charged polymer side chain and low potential on the cathode. Therefore, it requires ultra-pure water in the operation condition.

Different cations may bring different challenges to the PEMWE. For example, some transition metals, such as Fe2+, once introduced into the membrane, may catalyze the chain formation of radicals (×OH, ×OOH, etc.) due to the Fenton reaction(3), which will cause the decomposition of the membrane. In addition, some common cations that exist in drinking water, such as Ca2+, Na+, and Mg2+, will migrate onto the cathode through the membrane and block the active sites of the catalyst(4). Moreover, typical radical scavengers such as Ce, may migrate through the membrane during the operation process(5) and become a source of contamination due to their mobility in the MEA.

In this study, we will investigate the impact of different concentrations of contamination, such as Ca2+ on the polarization curve of PEMWC and discuss the possible influence on its hydrogen crossover. To further clarify the contamination impact on the cathode, the performance of MEAs with different catalyst loadings on the cathode when subjected to cations, will be presented and discussed. In addition, several analytical instruments, such as ion chromatography (IC), inductive coupled plasma mass spectroscopy (ICP-MS), and thermo-gravimetric analysis (TGA) will be utilized to gain deeper insight into the degradation process of these contaminated MEAs.

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Numerical Measurement of the Effective Electrical Conductivity of Electrolyte-Gas Bubble Dispersions
Authors: Pari Arvind , Padding Johan Tiemen , Hartkamp Remco
Published: September 2023

Bubble formation during water electrolysis is inevitable. Apart from mass and heat transfer limitations, the presence of these bubbles causes a decrease in the local electrical conductivity of the electrolyte, thereby contributing further to the ohmic resistance of the system. Experimental and theoretical studies have shown that the effective electrical conductivity of an electrolyte-gas bubble dispersion depends on the volume fraction of gas bubbles. However, these studies do not provide insight into the dependence of conductivity on the geometric and spatial parameters of the dispersion, such as the size distribution of the bubbles or their spatial arrangement.

Experimentally, the conductivity of such dispersions can be measured using the four-electrode conductivity measurement technique. In this talk, I will present a numerical rendition of this experimental technique to measure the conductivity of an electrolyte dispersed with gas bubbles, using the lattice Boltzmann method. The computational nature of the method lends itself well to investigating systems with different bubble size distributions and spatial configurations. The model also offers the flexibility to specify the surface charge density of the dispersed bubbles. The visualization of the ionic flux around these dispersed bubbles provides insights into the motion of ions along the paths of least resistance, and therefore a better understanding of the behavior of such systems.

The effective conductivity of bubble dispersions with varying degrees of randomness in their spatial arrangement has been measured, ranging from a regularly packed array of bubbles to a completely random packing. We observed that the numerically measured conductivity deviates from that predicted theoretically at high bubble volume fractions. Moreover, for the same bubble volume fraction, different spatial arrangements yield different values of conductivity, thus highlighting the influence of spatial arrangement of the bubbles on the effective conductivity of the dispersion. Additionally, the spread (standard deviation) of the numerically measured conductivity about the mean value for a given bubble volume fraction is observed to be larger at moderate volume fractions, in comparison to very dilute and densely packed dispersions. This can be explained by the fact that at moderate bubble volume fractions, there is a larger probability for the formation of random bubble clusters that hinder the movement of ions. Such clusters are unlikely in dilute cases and are universal in the dense limit, and as a consequence, less variation in the resulting effective conductivity is observed for the two limiting cases. This furthermore indicates the importance of spatial arrangement on the effective conductivity of such dispersions.