Semiconductor

Hall effect measurements on undoped Al0. 25Ga0. 75N/GaN heterostructures grown by a metalorganic chemical vapour deposition (MOCVD) technique have been carried out as a function of temperature (20–350 K) and magnetic field (0–1.5 T). Magnetic field dependent Hall data were analysed using the quantitative mobility spectrum analysis (QMSA) technique. The mobility and density within the two-dimensional electron gas (2DEG) at the Al0. 25Ga0. 75N/GaN interface and within the underlying GaN layer were ...

A strong plasmonic enhancement of photoluminescence (PL) decay rate in quantum dots (QDs) coupled to an array of gold-coated nanocups is demonstrated. CuInS2 QDs that emit at a wavelength that overlaps with the extraordinary optical transmission (EOT) of the gold nanocup array are placed in the cups as solutions. Time-resolved PL reveals that the decay rate of the QDs in the plasmonically coupled system can be enhanced by more than an order of magnitude. Using finite-difference time-domain (FDTD) simulations, it is shown that this enhancement in PL decay rate results from an enhancement factor of ≈100 in electric field intensity provided by the plasmonic mode of the nanocup array, which is also responsible for the EOT. The simulated Purcell factor approaches 86 at the bottom of the nanocup and is ≈3–15 averaged over the nanocup cavity height, agreeing with the experimental enhancement result. This demonstration of solution-based coupling between QDs and gold nanocups opens up new possibilities for applications that would benefit from a solution environment such as biosensing.

In the present research oleic acid carbon dots have been optimized for high-thermal stability applications via suitable thermal-tuning in liquid as well as in anhydrous medium. The intended tuning of the nano-dimensional particles was achieved by Fischer Esterification using suitable hydroxyl group-bearing moieties. The achieved external surface functionalization was fast, easy and cost-effective. The synthesized carbon dots were characterized using UV-Vis, Fluorescence, FT-IR, SEM, TGA and DSC techniques. The coalesce of the stated instrumentations derived a possible mechanistic approach and relationship regarding the thermal-tuning of the carbon dots for a deeper overview. The band-gap energy measurement revealed exclusive wide band-gap semiconductor characteristics of the investigated nanoparticles. Further, the fabrication of carbon dots on cotton fabric potentialized a new class of synthetic flame-retardant free high temperature resistant textiles, deemed essential for a greener future. The enhanced nature of these carbon dots with requisite alteration capabilities for temperatures as high as 800 °C could certainly improve the applicability of these particles in future electronic advancements.

The semiconductor integrated circuits (IC) manufacturing processes consume a huge amount of high-purity water (HPW) at different grades of quality. In order to conserve natural resources and reduce production costs, a novel process-to-process water recycling system was developed from this study. The pilot-scale system, consisting of ultrafiltration (UF) followed by a polishing loop, was able to produce low grade HPW (4.5 m3/h) from the wastewater discharged from wafer backgrinding and sawing processes with an overall recovery rate of 90%. The reclaimed water was directly supplied to other IC assembly processes such as electroplating and marking that consumed HPW of lower purity. The wastewater treatment system was integrated with the HPW system on site to achieve the best recycling practice. In comparison with the conventional recycling methodologies, process-to-process recycling offered a few advantages including: higher recovery rate; improved quality performance; minimized operating issues; and reduced return of investment (ROI) period. In comparison with the HPW production unit cost ranging from US$ 2.38–5.28 m−3, the reclaimed wastewater unit cost was US$ 0.85 m−3 only. The system has been operated in a continuous mode for the past 2 years without any quality issue being raised.

The results of an ongoing collaborative project between the New Jersey Institute of Technology (NJIT) and SEMATECH on the temperature-dependent emissivity of silicon-related materials and structures are presented in this study. These results have been acquired using a spectral emissometer. This emissometer consists of a Fourier Transform Infra-Red (FTIR) spectrometer designed specifically to facilitate simultaneous measurements of surface spectral emittance and temperature by using optical techniques over the near- and mid-IR spectral range and temperatures ranging from 300 K to 2000 K. This noncontact, real-time technique has been used to measure radiative properties as a function of temperature and wavelength for a wide range of silicon-related materials and structures. The first results of the temperature and wavelength dependent emissivity and hence refractive index of silicon nitride, in the literature, is presented in this study

En este artículo se evidencia la relación entre la temperatura de trabajo y la corriente, como herramienta que posibilita la efectividad del uso de imágenes Termográficas en el procedimiento de inspección de sistemas electrónicos de potencia. Se comprueba mediante los datos técnicos que da el fabricante, cálculos teóricos de parámetros eléctricos y mediciones realizadas en el sistema bajo prueba.

Introduction
This lab session has a purpose of practical implementation of theoretical knowledge about transistors. There are four parts in the work:
• NPN and PNP Transistors
• Transistors Biasing
• Q point stabilization
Apparatus
The following equipment was used during the lab:
• MCM3/EV board
• Power supply PSLC or PS1-PSU/EV
• Accessories
As in the previous lab, the whole lab work is done with the MCM/EV board. The oscilloscope was used for the visualization of the waveforms. Screwdriver was used for the variable resistor configuration.

This paper examines the semiconductor's industry growing importance as a strategic technology in the modern industrial system and in contemporary warfare. It also analyzes this industry's evolution in China and the Chinese semiconductor industrial policy over the last years. We review the Chinese interpretation of the 'revolution in military affairs' and China's perception of its backwardness as well as the possibilities of catch-up and evolution in the most sophisticated segments of this productive chain through domestic firms and indigenous innovation.

Este libro brinda una introducción a la electrónica en semiconductores -también llamada de estado
sólido- para carreras de ingeniería en electrónica, electricidad, computadoras, comunicaciones, control y sistemas. Provee una explicación de los mecanismos de conducción eléctrica en Silicio,
que luego se utiliza para el desarrollo de cuatro dispositivos fundamentales de la electrónica actual: el diodo de juntura, el capacitor Metal-Oxido-Semiconductor (MOS), el transistor MOS, y el transistor bipolar de juntura. El libro conduce al estudiante a que entienda el funcionamiento de cada dispositivo, partiendo de sus principios fundamentales, y que a partir de allí, comprenda en profundidad los diferentes modelos eléctricos que puede utilizar para representarlo, sus alcances y limitaciones. El objetivo último es que el estudiante conozca y sepa utilizar los distintos modelos de los dispositivos electrónicos, de acuerdo al rango de amplitud y frecuencia, para su utilización futura en el diseño y análisis de circuitos.

Operational Amplifier (Op Amp) is a three terminal electronic device which has two inputs of high impedance. The first input is called inverting (represented by ‘-‘), and the other terminal is called non-inverting input. The third terminal serves as output port, where signal is usually amplified by some gain (A), depending on the nature of op amp and input characteristics. 
In this lab session we build op amp circuits and carry out various calculations of op amp characteristics. At the end of this lab, we are to strengthen theoretical knowledge by gaining hands on experience. This lab covers:
- Inverting Amplifiers 
- Non-inverting Amplifiers 
- Summing Amplifiers

Of the III-Nitride family the AlN/GaN heterojunction has demonstrated the largest combined polarization charge and energy band osets available in the system. Engineering the polarization fields through varying the AlN thickness leads to two-dimensional electron gas densities (2DEGs) that may be tailored between 0.5 - 5 x1013 cm􀀀2. Furthermore, the ultra-thin (< 5 nm) barrier and excellent transport properties of this all binary heterostructure make it well suited for high electron mobility transistor applications where high frequency and high current are required. This work encompasses various design aspects of GaN-based High Electron Mobility Transistors (HEMTs) which ultimately result in the realization of several generations that utilize the AlN/GaN heterostructure.

HEMTs fabricated from high-mobility, low sheet resistance heterostructures have achieved drain current densities up to 2.3 A/mm and transconductance of 480 mS/mm, which set new benchmarks for GaN-based HEMTs. Ultra-thin pre-metallization etching has been employed for the rst time to reduce ohmic contact resistance for AlN/GaN HEMTs and has enabled small signal frequency performance in excess of 100 GHz. Moll's method for delay time extraction has been utilized to extract an effective electron velocity in the intrinsic region of the AlN/GaN HEMT and was found to be  1.2 x107 cm/s.

By leveraging the allowable thickness window of the AlN barrier along with the high density 2DEGs that result, several novel HEMT devices have been designed and realized. High Al-content AlxGa1􀀀xN back barriers have been employed for improved 2DEG confinement in several new variations of the ultra-thin AlN/GaN HEMT. A dual, parallel-channel AlN/GaN-based HEMT structure is designed and realized for the first time as an epitaxial approach to mitigating DC-RF frequency dispersion. These structures emphasize the facilitation of new device designs that are made possible through the particular qualities the AlN/GaN heterostructure possesses.

Slot die coating is growing in popularity because it is a low operational cost and easily scaled processing technique for depositing thin and uniform films rapidly, while minimizing material waste. The complex inner geometry of conventional slot dies require expensive machining that limits accessibility and experimentation. In order to overcome these issues this study follows an open hardware approach, which uses an open source 3-D printer to both fabricate the slot die and then to functionalize a 3-D slot die printing system. Polymer materials are tested and selected for compatibility with common solvents and used to fabricate a custom slot die head. This slot die is then integrated into a 3-D printer augmented with a syringe pump to form an additive manufacturing platform for thin film semiconductor devices. The full design of the slot die system is disclosed here using an open source license including software and operational protocols. This study demonstrates that functional lab-grade slot dies may be 3-D printed using low-cost open source hardware methods. A case study using NiO2 found an RMS value 0.486 nm, thickness of 17 to 49nm, and a maximum optical transmission of 99.1%, which shows this additive manufacturing approach to slot die depositions as well of fabrication is capable of producing viable layers of advanced electronic materials. Using this method, a cost savings of over 17,000% was obtained when compared to commercial slot die systems for laboratories.

Manuscript received Sep. 20, 2006; revised Feb. 16, 2007. Dept. Electrical and Computer Engineering Pohang University of Science and Technology San 31, Hyojadong, Pohang, Kyungbuk , 790-784, Korea TEL : +82-54-279-5025, FAX : +82-54-279-5026 E-mail : hjpark@postech. ...

The photocatalytic reduction of CO 2 into light hydrocarbons using sunlight and water is a challenging reaction involving eight electron transfer steps; nevertheless, it has great potential to address the problem of rising anthropogenic carbon emissions and enable the use of fossil fuels in a sustainable way. Several decades after its first use, TiO 2 remains one of the best performing and most durable photocatalysts for CO 2 reduction albeit with a poor visible light absorption capacity. We have used flame annealing to improve the response of TiO 2 to visible photons and engineered a nanotubular morphology with square-shaped cross-sections in flame-annealed na-notubes. An enhanced CH 4 yield was achieved in the photoreduction of CO 2 using flame annealed TiO 2 nano-tubes, and isotope labeled experiments confirmed the reaction products to originate from the CO 2 reactant. Flame-annealed TiO 2 nanotubes formed in aqueous electrolyte (FANT-aq) yielded 156.5 μmol g catalyst-1 .hr-1 of CH 4 , which is in the top tier of reported performance values achieved using TiO 2 as a stand-alone photocatalyst. This performance resulted because appreciable amounts of CH 4 were generated under visible light illumination as well. TiO 2 nanotubes exhibited CO 2 photoreduction activity up to a wavelength of 620 nm with visible light driven photocatalytic activity peaking at 450 nm for flame annealed TiO 2 nanotubes. Isotope labelling studies, using GC-MS and gas-phase FTIR, indicated photoreduction of 13 CO 2 to 13 CH 4. The detection of 13 CO in the product mixture, and the absence of HCHO and HCOOH provides strong support for the photoreduction proceeding along a carbene pathway. The enhanced CO 2 photoreduction performance of FANT-aq is attributed to increased visible light absorption, square morphology, and the presence of rutile as the only crystalline phase with (110) as the dominant plane.

"Visualizing Art History: Experimental Animation and Its Mentor, Jules Engel" by Janeann Dill, phd, mfa

A dictionary begins when it no longer gives the meaning of words, but their tasks.
--- Georges Bataille

It is most often the case when I refer to my work as experimental animation that I am met with the question, what is experimental animation? I am instantly reminded of a story about Louis Armstrong in conversation with Johnny Carson who asked Armstrong, “What is jazz?” Louis Armstrong enthusiastically responded, “Well if you don’t know what it is, I sure as hell can’t tell you!”

In some ways, Louis Armstrong’s response might be said to be universal for questions having to do with art, in that any attempt to offer definition tends to further confuse, bind, constrict and/or be irrelevant, rather than to clarify meaning. As a scholar and as an artist, I am most interested in the unanswerable. As I understand it, to ask the unanswerable is the beginning of an event … if you will, an event of language, timing and gesture, experimentation and conceptualizing. The more important consideration in a “what is ____?” question is not the answer, but the asking.. How is it we know so little about the art form?

Frog-leg robots have been widely used for handling silicon wafers inside the vacuum environment of semiconductor manufacturing machines. In order to enhance stiffness, frog-leg robots adopt a parallel structure. A main challenge of controlling wafer handling robot is avoiding vibration, which is the major cause of wafer sliding and particle contamination. This paper presents two control approaches to improve the performance of frog-leg robots. First, in addition to the basic tri-loop PID feedback controller, torque offset is injected to the input of the robot to compensate the robot’s nonlinear dynamics. This reduces the following error and major vibration. The torque offset is calculated based on identified robot dynamics. Second, a test based optimization method is developed to tune the gains of the feedback controller. Wafer vibration is measured and analyzed to score the system performance. Comparison results show that the proposed control scheme gives much improved performance.

The heteroepitaxial growth of the new ternary, group-IV, semiconductor material, Si1-x-yGexCy on Si(100), has been investigated. The epitaxial quality of Si1-x-yGexCy is found to be inferior to that of Si1-xGex with similar Si/Ge concentration ratio, grown under identical conditions, and the quality deteriorates with increasing C fraction. Also, the surface roughness, as studied by tapping mode atomic force microscopy, increases with increasing C fraction as well as with increasing Ge fraction, suggesting a transition from Frank-van der Merve to Stranski-Krastanov type growth. We suggest that the very large mismatch between the average bond length in the Si1-x-yGexCy material, as determined by Vegard's law, and the equilibrium Si-C bond length, weakens the Si-C bonds and reduces the elastic range of the material, thus lowering the barrier for dislocation and stacking fault formation. The change in elasticity may also be responsible for the change in growth morphology, either directly by a lowered barrier for island formation or indirectly through the formation of defects. A decrease in Ge incorporation in the Si1-x-yGexCy films with increasing C incorporation suggests a repulsive Ge-C interaction. Moreover, we observe a C-rich, Ge-deficient precursor phase to SiC precipitates at a growth temperature of 560 degrees C, whereas at 450 degrees C no such phase can be observed. The temperature dependence of the precursor formation is consistent with C bulk diffusion. Infrared absorption measurements cannot be used to detect the precursor phase. Finally, the onset of epitaxial breakdown is discussed and an accurate and independent determination of the C fraction and its substitutionality is emphasized. (

In order to see effects of interfacial (with and without different graphene (GP) + Ca1.9Pr0.1Co4Ox-doped PVA) layer on the electrical characteristics of conventional Au/n-Si (MS) contacts. Therefore, Au/(GP + Ca1.9Pr0.1Co4Ox-doped PVA)/n-Si (MPS) structures were fabricated with different rates of (%3 GP, %7 GP) PVA and were fabricated on same n-Si wafer. Au/n-Si (MS), Au/PVA/n-Si, Au/%3GP + Ca1.9Pr0.1Co4Ox-doped PVA/n-Si and Au/%7GP + Ca1.9Pr0.1Co4Ox-doped PVA/n-Si structures were fabricated and their main electrical characteristics compared each other by using current–voltage (I–V) methods. The forward and reverse bias current voltage (I–V) characteristics of with and without GP + Ca1.9Pr0.1Co4Ox-doped PVA/n-Si at room temperature were studied to investigate its main electrical parameters. The energy density distribution profile of the interface states (Nss) was obtained from the forward bias I–V data by taking into account voltage dependent ideality factor (n(v)) and effective barrier height (Φe) and they increase from at about mid-gap energy of Si to bottom of conductance band edge. In addition, voltage dependent profile of resistivity of the structure was obtained from I–V data for four different structures. The analysis of experimental results reveals that the existence of GP + Ca1.9Pr0.1Co4Ox-doped PVA interfacial layer improves the performance of MS structure. In order to determine the dominant current-transport mechanism (CTM) in the whole forward bias region of these structures, the double logarithmic forward bias I–V plots were also drawn. These plots exhibit two distinct linear region with different slopes which are corresponding to intermediate and high forward bias voltages. The slope of these plots show that in the region 1 (low biases) the dominant CTM is trap-charge-limited current (TCLC), whereas in the region 2 (high biases) is space-charge-limited current (SCLC) for four diodes.

Synthesis of Ag3PO4 photocatalyst under the varied concentrations of AgNO3 and Na2HPO4·12H2O as starting material has been successfully synthesized using the co-precipitation method. The concentration of AgNO3 is 0.1, 0.5, 1.0, and 2.0 M, whereas Na2HPO4·12H2O is 0.03, 0.17, 0.33, and 0.67 M, respectively. The co-precipitations were carried out under aqueous solution. As-synthesized photocatalysts were examined to degrade Rhodamine B (RhB) under blue light irradiation. The results showed that varying concentrations of starting materials affect the photocatalytic activities, the intensity ratio of [110]/[200] facet plane, and their bandgap energies of Ag3PO4 photocatalyst. The highest photocatalytic activity of the sample was obtained by synthesized using the 1.0 M of AgNO3 and 0.33 M of Na2HPO4·12H2O (AP-1.0). This is due to the high [110] facet plane and increased absorption along the visible region of AP-1.0 photocatalyst. Therefore, this result could be a consideration for the improvement of Ag3PO4 photocatalyst.

In this paper, for the first time, we propose a partial silicon-on-insulator (P-SOI) lateral double-diffused metal-oxide-semiconductor-field-effect-transistor (LDMOSFET) with a modified buried layer in order to improve breakdown voltage (BV) and self-heating effects (SHEs). The main idea of this work is to control the electric field by shaping the buried layer. With two steps introduced in the buried layer, the electric field distribution is modified. Also a P-type window introduced makes the substrate share the vertical voltage drop, leading to a high vertical BV. Moreover, four interface electric field peaks are introduced by the buried P-layer, the Si window and two steps, which modulate the electric field in the SOI layer and the substrate. Hence, a more uniform electric field is obtained; consequently, a high BV is achieved. Furthermore, the Si window creates a conduction path between the active layer and substrate and alleviates the SHE. Two-dimensional simulations show that the BV of double step partial silicon on insulator is nearly 69% higher and alleviates SHEs 17% in comparison with its single step partial SOI counterpart and nearly 265% higher and alleviate SHEs 18% in comparison with its conventional SOI counterpart.