Green attributes converged within multifunctional technology products

This article analyzes the way in which the convergence of green attributes in multifunctional technological products influences consumers’ purchase intentions. Due to the recent growth in convergent products, technology users and consumers must choose among numerous different applications that can be perceived as either utilitarian or hedonic. This article suggests that new products launched on the market include attributes that are connected to sustainability and provide added value to consumers in their process of decision making. The primary question addressed in this article concerns whether an increase or decrease in consumer intention is based on the perception of the product’s utility, and the consumer’s prior experience and attitude toward green products. A 2 × 2 × 2 experiment was conducted to evaluate utilitarian or hedonic convergence, green attribute integration, and predisposition for (involvement with) green products. We propose that consumer value increases for those consumers with a high perception of green integration connected to a high predisposition for green devices, which increases the utilitarian value of the product or justifies the hedonic purchase of technological equipment.     

The use of mobile technology for online shopping and entertainment among older adults in Finland

Older adults are becoming an important market segment for all internet-based services, but few studies to date have considered older adults as online shoppers and users of entertainment media. Utilising the concept of life course, this article investigates the use of mobile technologies for online shopping and entertainment among consumers aged 55 to 74. The data were collected with a web-based survey completed by a panel of respondents representing Finnish television viewers (N = 322). The results reveal that consumers aged 55 to 74 use a smartphone or tablet to purchase products or services online as often as younger consumers. In contrast, listening to internet radio and watching videos or programmes online with a smartphone or tablet are most typical for younger male consumers. The results demonstrate that mobile-based online shopping is best predicted by age, higher education, and household type (children living at home), and use of entertainment media by age and gender.     

An integrated project of entrepreneurship and innovation in engineering education

This paper presents a new line of project based learning in the School of Engineering of University of Minho: the Innovation and Entrepreneurship Integrated Project (IEIP). Four groups, each one composed of students from different engineering integrated master courses – Mechanical, Industrial Electronics and Computers, Polymer, Industrial Management – compete against each other in developing or improving commercial products manufactured by actual industries. There have been so far five editions of the IEIP, with five different companies and five diverse products, however, all these products included components that required knowledge from all the engineering courses involved. Only with the cooperation between the students of the various courses that compose each multidisciplinary team, the success is attainable. As each student has to deal with various engineering scopes, students’ technical skills are greatly enlarged and they acquire a multidisciplinary knowledge that was not possible in another way. Their soft skills like project management, teamwork, communication ability and personal development, which are valuable requisites for their future employers, are also improved. The participating industries also take advantage of the project: the groups competing against each other act as a multiskilled work force, actually making proposals capable of improving their products, their efficiency, and reducing costs.     

Study on crosstalk characteristic of carbon nanotube through silicon vias for three dimensional integration

Coupling noise induced by through silicon vias (TSVs) is expected to be a major concern for three dimensional integrated circuits (3-D ICs) system design. Using equivalent electrical parameters for carbon nanotube (CNT) TSV interconnects, a lumped crosstalk noise model is introduced to capture the TSV-to-TSV coupling noise in CNT via based 3-D ICs and validated with multiple conductor transmission line (MTL) simulation results. The effect of geometrical and material parameters involved on the noise transfer function and peak crosstalk noise, such as insulation thickness, TSV–TSV spacing, TSV height, TSV radius, substrate conductivity and metallic CNT density, is investigated with the proposed model. Simulation results show that the TSV coupling can be divided into three frequency behavior regions. Three approaches using driver sizing, grounded vias shielding and air gap-based silicon-on-insulator (SOI) technique are proposed to mitigate TSV crosstalk coupling noise. The proposed approaches are demonstrated in frequency- and time- domain simulations. They provide the reduction in full-band noise transfer function by an average of 11.71 dB, 24.85 dB and 3.46 dB, and the decrease in 1 GHz peak noise voltage by 53.24 mV, 40.72 mV and 15.1 mV.     

Degradation of all-inkjet-printed organic thin-film transistors with TIPS-pentacene under processes applied in textile manufacturing

Printed electronics represent an alternative solution for the manufacturing of low-temperature and large area flexible electronics. The use of inkjet printing is showing major advantages when compared to other established printing technologies such as gravure, screen or offset printing, allowing the reduction of manufacturing costs due to its efficient material usage and the direct-writing approach without requirement of any masks. However, several technological restrictions for printed electronics can hinder its application potential, e.g. the device stability under atmospheric or even more stringent conditions. Here, we study the influence of specific mechanical, chemical, and temperature treatments usually appearing in manufacturing processes for textiles on the electrical performance of all-inkjet-printed organic thin-film transistors (OTFTs). Therefore, OTFTs where manufactured with silver electrodes, a UV curable dielectric, and 6,13-bis(triisopropylsilylethynyl) pentance (TIPS-pentacene) as the active semiconductor layer. All the layers were deposited using inkjet printing. After electrical characterization of the printed OTFTs, a simple encapsulation method was applied followed by the degradation study allowing a comparison of the electrical performance of treated and not treated OTFTs. Industrial calendering, dyeing, washing and stentering were selected as typical textile processes and treatment methods for the printed OTFTs. It is shown that the all-inkjet-printed OTFTs fabricated in this work are functional after their submission to the textiles processes but with degradation in the electrical performance, exhibiting higher degradation in the OTFTs with shorter channel lengths (L = 10 μm).     

Process control for 32 nm imprint masks using variable shape beam pattern generators

Step and Flash Imprint Lithography (S-FIL^®) is a unique method that has been designed from the beginning to enable precise overlay for creating multi-level devices. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of templates (imprint masks).For device manufacturing, one of the major technical challenges remains the fabrication of full-field 1X templates with commercially viable write times. Recent progress in the writing of sub-40 nm patterns using commercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub-32 nm node. Here we report the critical dimension (CD) uniformity and process latitude of dense 32 nm patterns from templates written with variable shape beam pattern generators. Uniformity on the template and in the imprinted field was 3.22 and 3.45 nm, 3σ. Process latitude during the writing of the template was improved by increasing both feature bias and exposure dose. As an example, the slopes for the 36 and 32 nm features are approximately 0.30 and 0.25 nm/μC/cm², respectively, indicating a substantial process window for exposure dose.     

Small molecule interlayer for solution processed phosphorescent organic light emitting device

Using a 4,4′,4′′-tris(N-carbazolyl)-triphenylamine (TCTA) small molecule interlayer, we have fabricated efficient green phosphorescent organic light emitting devices by solution process. Significantly a low driving voltage of 3.0 V to reach a luminance of 1000 cd/m² is reported in this device. The maximum current and power efficiency values of 27.2 cd/A and 17.8 lm/W with TCTA interlayer (thickness 30 nm) and 33.7 cd/A and 19.6 lm/W with 40 nm thick interlayer are demonstrated, respectively. Results reveal a way to fabricate the phosphorescent organic light emitting device using TCTA small molecule interlayer by solution process, promising for efficient and simple manufacturing.     

Metal-Film Fiber Attenuators with Flat Spectral Response

Metal-film fiber attenuators have been designed, fabricated, and tested. The devices feature a constant attenuation in the wavelength range 1.2–1.6 μm, short overall length ( ≈ 20 mm), high return loss ( > 50 dB), and low cost. After reviewing the manufacturing procedure, we show that an accurate finishing of the fiber end before metal deposition is a key point in increasing repeatability and reducing dispersion of the absolute attenuation value.     

Device to circuit reliability correlations for metal gate/high-k transistors in scaled CMOS technologies

Metal gate/high-k stacks are in CMOS manufacturing since the 45 nm technology node. To meet technology performance and yield targets, gate stack reliability is constantly being challenged. Assessing the associated reliability risk for CMOS products relies on a solid understanding of device to circuit reliability correlations. In this paper we summarize our findings on the correlation between device reliability and circuit degradation and highlight areas for future work to focus on.     

Simple-structured efficient white organic light emitting diode via solution process

High-efficiency white emission is crucial to the design of energy-saving display and lighting panels, whereas solution-process feasibility is highly desirable for large area-size and cost-effective roll-to-roll manufacturing. In this study, we demonstrate highly-efficient, bright and chromaticity stable white organic light emitting diodes (OLEDs) with solution-processed single emissive layer. The resultant best white OLED shows excellent electroluminescence performance with forward-viewing external quantum efficiency, current efficiency and power efficiency of 22.7%, 48.8 cd A^− 1 and 27.8 lm W^− 1 at 100 cd m^− 2, respectively, with a maximum luminance of 19,590 cd m^− 2. Furthermore, we also observed an increment of 112% in the power efficiency, 86.9% in the current efficiency and a decrement of 39.2% in the external quantum efficiency at 100 cd m^− 2 as the doping concentration of blue dye was increased from 10 wt% to 25 wt% in the devices. The better efficiency performance may be attributed to the effective exciton-confining device architecture and low-energy barrier for electrons to inject from the hole-blocking electron-transport layer to the host layer.     

Mechatronics and control of a long-range nanometer positioning servomechanism

Since the manufacturing accuracy of semiconductor and biochemical products is increased to nanometer level gradually, the development of long-range positioning servomechanism has become a hot research topic. The piezoelectric actuator is widely chosen to design precise positioning system for achieving the sub-micro or nano-position. However, their motion range is only 100 μm. Here, a long-range nanometer positioning servo system with AC servo motor and ball screw mechanism is built for the precision manufacturing purpose. It needs a special design control algorithm to obtain quick transient response and precise steady state accuracy. A new model-free fuzzy controller is designed to control this low-cost motion stage for achieving nanometer step response positioning. It has a novel gain auto-tuning strategy in response to the transient or steady state responses requirement. The experimental results show that this approach can reach more than 30 cm stroke and the step response error is less than 60 nm.     

Single-grain Si thin-film transistors SPICE model,analog and RF circuit applications

Single-grain thin-film transistors (SG-TFTs) fabricated inside location-controlled using μ-Czochralski process exhibit SOI-FETs like performance despite processing temperatures remaining below 350 °C. Thus, the SG-TFT is a potential technology for large-area highly-integrated electronic system and system-in-package, taking advantage of the system-on-flexible substrate and low manufacturing cost capabalities. The SG-TFT is modeled based on the BSIMSOI SPICE model where the mobility parameter is modified to fit the SG-TFT behavior. Therefore, analog and RF circuits can be designed and benchmarked. A two-stage telescopic cascode operational amplifier fabricated in a prototype 1.5 μm SG-TFT technology demonstrates DC gain of 55 dB and unity-gain bandwidth of 6.3 MHz. A prototype CMOS voltage reference demonstrates a power supply rejection ratio (PSRR) of 50 dB. With unity-gain frequency, f_T, in the GHz range, the SG-TFT can also enable RF circuits for wireless applications. A 12 dB gain RF cascode amplifier with integrated on-chip inductors operating in the 433 MHz ISM band is demonstrated.     

New antenna design approach – 3D polymer printing and metallization. experimental test at 14–18 GHz

This paper proves a new approach for rapid prototyping of radio antennas through 3D printing and chemical metallization. For this purpose, a standard metal pyramidal horn prototype is compared with its 3D printed replica. Three different 3D polymer printers are tested. The printed samples are assessed nondestructively by an X-ray Industrial Computed Tomography (CT) scanner, and then metalized via chemical deposition and chemical-electrochemical deposition. Copper with two different layer thicknesses and nickel materials are deployed and verified as a metallization opportunity. Again the CT scanner, X-ray fluorescent analysis and nanoindentation technique were used to perform the metallization quality estimation. As a result, a qualitative polymer prototype was produced having weight of 13 g – ten times lighter than the original. The prototype was successfully metalized and was able to be soldered. The radio-measurement comparison with the metal original for frequencies 14–18 GHz showed no significant differences. Finally, a simple dynamometric test confirmed the bonding between the metal and the polymer. To the best of our knowledge this is the first known comprehensive analysis of the possibility to print 3D lightweight wideband polymer antenna prototypes with a stable chemical metallization and radio properties very close to the original at 14–18 GHz.     

Enabling high-efficiency organic light-emitting diodes with a cross-linkable electron confining hole transporting material

Wet-process enables flexible, large area-size organic devices to be fabricated cost-effectively via roll-to-roll manufacturing. However, wet-processed devices often show comparatively poor performance due to the lack of solution-process feasible functional materials that exhibit robust mechanical properties. We demonstrate here a cross-linkable material, 3,6-bis(4-vinylphenyl)-9-ethylcarbazole (VPEC), to facilitate the injection of hole and meanwhile effectively confine electron to realize, for examples, high efficiency organic light-emitting diodes, especially at high luminance. The VPEC shows a hole mobility of 1 × 10⁻⁴ cm² V⁻¹ s⁻¹ and a triplet energy of 2.88 eV. Most importantly, the VPEC not only works for devices containing low band-gap red or green emitters, but also for the counterpart with high band-gap blue emitter. With the electron confining hole transporting material, the power efficiency of a studied red device, at 1,000 cd m⁻² for example, is increased from 8.5 to 13.5 lm W⁻¹, an increment of 59%, and the maximum luminance enhanced from 13,000 to 19,000 cd m⁻², an increment of 46%. For a high triplet energy blue emitter containing device, it is increased from 6.9 to 8.9 lm W⁻¹, an increment of 29%, and the maximum luminance enhanced from 9,000 to 11,000 cd m⁻², an increment of 22%.     

Thermal-aware design and fault analysis of a DC/DC parallel resonant converter

In this paper a 3-D electrothermal (ET) analysis of a DC–DC parallel resonant converter (PRC) for constant current (CC) application is presented. A full 3-D ET simulation approach is proposed at application level to provide a support for the design stage and to analyse possible fault conditions inside the active devices. Simulations and measurements have been performed on a 100 W–2 A prototype of a PRC-CC circuit with 80 kHz nominal switching frequency.In particular, in the reported case study, the analysis has been focused on the full-bridge section of the circuit in order to prove the effect of the soft switching operation, introduced by the resonant technique, and consider the effect of possible fault conditions. To this purpose an unexpected short-circuit condition on a power MOSFET composing the H-bridge is considered, to evaluate the ET circuit behaviour and the time-to-failure of the power section. Considerations are carried out in terms of minimum requirements of protection circuits which must be fulfilled in order to avoid catastrophic system failure.A second power converter, rated for 1.5 kW, has been then designed, based on the same circuital topology, and an ET simulation has been performed in order to carry out considerations on the effect of mismatches among the input bridge devices.     

High rectifier output voltages with printed organic charge pump circuit

It is known that in many wireless organic electronic applications the required supply voltage is higher than the accessible signal amplitude. Therefore, voltage multiplier circuits are needed in many cases. We report a gravure printed organic charge pump circuit operating at 13.56 MHz suitable for rectified voltage amplification in printed electronic devices. The circuit, consisting of four diodes and four capacitors, has been monolithically printed using only high volume production compatible manufacturing methods. With 10 V AC input the output of the circuit at 13.56 MHz is 8.4 V and 11.8 V using 1 MΩ and 10 MΩ output loads, respectively. At 13.56 MHz the output voltage of the charge pump is three times higher than the output of a half-wave rectifier. The results demonstrate the possibility to print efficient high frequency (HF) charge pump circuits to meet the supply voltage requirements of the printed electronic applications.     

Numerical design of a 100 W, 38 dB gain,W-band multi-section serpentine waveguide vacuum electronic TWT

The serpentine waveguide circuit is a robust beam-wave interaction circuit for W-band TWTs. Here presented the electromagnetic properties and design methodology for W-band multi-section SWG traveling wave tube. Cold-test (in absence of electron beam) numerical design performed theoretically and further optimized/validated with standard simulation code to predict the dispersion, interaction impedance, ohmic-loss and small-signal gain. Numerical simulation for the quarter wave transformer couplers with SWG circuit geometry shown the return-loss less than −20 dB for the 5% frequency band. Later, in systematic manner, hot-test (in presence of electron beam) numerical design performed for multi-section TWT by using standard particle-in-cell 3-D simulation code. The three section, 60 periods SWG TWT predicted peak radiation power 130 W at target frequency 94 GHz, 39.5 dB saturated gain, 5.3% instantaneous 3-dB frequency bandwidth, and 6.5% electronic efficiency.     

Ultra-flattened chromatic dispersion and highly nonlinear photonic crystal fibers with ultralow confinement loss employing hybrid cladding

In this paper, two new types of dispersion-flattened photonic crystal fibers (DF-PCFs) with highly nonlinear and ultralow confinement loss are proposed. These new PCF structures adopt hybrid cladding with different air-holes diameters, pitches and air-holes arranged fashions. In order to analyze the proposed PCFs, the full-vector finite element method with anisotropic perfectly matched layers has been used. Results show that the ultra-flattened dispersion of 0.931 ps/(nm km) (DF-PCF1) and 1.533 ps/(nm km) (DF-PCF2) can be achieved in the wavelength range from 1.3 to 1.6 μm with confinement losses lower than 0.001 dB/km in the same wavelength range. Meanwhile, the nonlinear coefficients of our proposed PCFs are greater than 23.83 W⁻¹ km⁻¹ (DF-PCF1) and 29.65 W⁻¹ km⁻¹ (DF-PCF2) at the wavelength of 1.55 μm, and two near-zero dispersion values of 0.328 ps/(nm km) (DF-PCF1) and −0.015 ps/(nm km) (DF-PCF2) can also be obtained at the same wavelength. Furthermore, the influence of manufacturing imperfections of parameters on dispersion and nonlinearity is discussed to verify the robustness of our design.     

RoHS compliance in safety and reliability critical electronics

In some safety- and reliability-critical applications, electronic products are subjected to harsh operating conditions for a lifetime ranging over ten years. For instance, the Emerson DVC6215 remote mount sensor has operating requirements from − 52 °C to 120 °C along with the ability to withstand high rates of temperature fluctuations during manufacture and vibration up to 50G's during use. Since safety- and reliability-critical products are designed for use in industries with specialized operating conditions, there is no standardized set of operating conditions for these products. As a result, such products were exempt from the EU's Restriction of Hazardous Substances (RoHS) directive passed in 2006. However, specific deadlines have been set for exempt industries in the 2011 recast version of the RoHS directive. This paper provides a systematic lead-free transition plan in safety- and reliability-critical products. Existing lead-free solder options for harsh environmental operating conditions are evaluated along with the pros and cons in RoHS compliance.     

Non-conductive film with Zn-nanoparticles (Zn-NCF) for 40 μm pitch Cu-pillar/Sn–Ag bump interconnection

Non-conductive film with Zn nano-particles (Zn-NCF) is an effective solution for fine-pitch Cu-pillar/Sn–Ag bump interconnection in terms of manufacturing process and interfacial reliability. In this study, NCFs with Zn nano-particles of different acidity, viscosity, and curing speed were formulated and diffused Zn contents in the Cu pillar/Sn–Ag bumps were measured after 3D TSV chip-stack bonding. Amount of Zn diffusion into the Cu pillar/Sn–Ag bumps increased as the acidity of resin increased, as the viscosity of resin decreased, as the curing speed of resin decreased, and as the bonding temperature increased. Diffusion of Zn nano-particles into the Cu pillar/Sn–Ag bumps are maximized when the resin viscosity became lowered and the solder oxide layer was removed. To analyze the effects of Zn-NCF on IMC reduction, IMC height depending on aging time was measured and corresponding activation energies for IMC growth were calculated. For the evaluation of joint reliabilities, test vehicles were bonded using NCFs with 0 wt%, 1 wt%, 5 wt%, and 10 wt% of Zn nano-particles and aged at 150 °C up to 500 h. NCF with 10 wt% Zn nano-particle showed remarkable suppression in Cu₆Sn₅ and (Cu,Ni)₆Sn₅ IMC compared to NCFs with 0 wt%, 1 wt%, and 5 wt% of Zn nano-particles. However, in terms of Cu₃Sn IMC suppression, which is the most critical goal of this experiment NCFs with 1 wt%, 5 wt%, and 10 wt% showed an equal amount of IMC suppression. As a result, it was successfully demonstrated that the suppression of Cu–Sn IMCs was achieved by the addition of Zn nano-particles in the NCFs resulting an enhanced reliability performance in the Cu/Sn–Ag bumps bonding in 3D TSV interconnection.