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Full-Text Articles in Nanoscience and Nanotechnology

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox Oct 2013

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …


Synthesis And Characterization Of Iron Pyrite Nanocrystals For Photovoltaic Devices, Scott Curtis Mangham May 2013

Synthesis And Characterization Of Iron Pyrite Nanocrystals For Photovoltaic Devices, Scott Curtis Mangham

Graduate Theses and Dissertations

Iron pyrite nanocrystals have been synthesized using a hot-injection method with a variety of amines and characterized with properties necessary for photovoltaic devices. The iron pyrite nanocrystals were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, optical absorption, micro-Raman, and micro-Photoluminescence. The optical absorbance spectra showed the large absorption in the visible and near infrared spectral range for the nanocrystals as well as to show the band gap. The face-centered cubic crystal structure of the iron pyrite nanocrystals was shown by matching the measured X-ray diffraction pattern to a face-centered cubic iron pyrite reference pattern. Using Bragg's law …


Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Feb 2013

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Faculty Publications

No abstract provided.


Ultra-Thin-Film Aln Contour-Mode Resonators For Sensing Applications, Matteo Rinaldi, Chiara Zuniga, Gianluca Piazza Feb 2013

Ultra-Thin-Film Aln Contour-Mode Resonators For Sensing Applications, Matteo Rinaldi, Chiara Zuniga, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of ultra-thin-film (250 nm) aluminum nitride (AlN) microelectromechanical system (MEMS) contour mode resonators (CMRs) suitable for the fabrication of ultra-sensitive gravimetric sensors. The device thickness was opportunely scaled in order to increase the mass sensitivity, while keeping a constant frequency of operation. In this first demonstration the resonance frequency of the device was set to 178 MHz and a mass sensitivity as high as 38.96 KHz⋅μm2/fg was attained. This device demonstrates the unique capability of the CMR-S technology to decouple resonance frequency from mass sensitivity.


Aln Contour-Mode Resonators For Narrow-Band Filters Above 3 Ghz, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza Feb 2013

Aln Contour-Mode Resonators For Narrow-Band Filters Above 3 Ghz, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) super high frequency (SHF) laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions in order to excite a contour-extensional mode of vibration in nano features of an ultra-thin (250 nm) aluminum nitride (AlN) film. In this first demonstration two-port resonators vibrating up to 4.5 GHz were fabricated on the same die and attained electromechanical coupling, kt^2, in excess of …


Ultra-Thin Super High Frequency Two-Port Aln Contour-Mode Resonators And Filters, Matteo Rinaldi, Chiara Zuniga, Chnegjie Zuo, Gianluca Piazza Feb 2013

Ultra-Thin Super High Frequency Two-Port Aln Contour-Mode Resonators And Filters, Matteo Rinaldi, Chiara Zuniga, Chnegjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the demonstration of a new class of ultra-thin (250 nm thick) super high frequency (SHF) AlN piezoelectric two-port resonators and filters. A thickness field excitation scheme was employed to excite a higher order contour extensional mode of vibration in an AlN nano plate (250 nm thick) above 3 GHz and synthesize a 1.96 GHz narrow-bandwidth channel-select filter. The devices of this work are able to operate over a frequency range from 1.9 to 3.5 GHz and are employed to synthesize the highest frequency MEMS filter based on electrically self-coupled AlN contour-mode resonators. Very narrow bandwidth (~ …


5-10 Ghz Aln Contour-Mode Nanoelectromechanical Resonators, Matteo Rinaldi, Chiara Zuniga, Gianluca Piazza Feb 2013

5-10 Ghz Aln Contour-Mode Nanoelectromechanical Resonators, Matteo Rinaldi, Chiara Zuniga, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of Super High Frequency (SHF) laterally vibrating NanoElctroMechanical (NEMS) resonators. For the first time, AlN piezoelectric nanoresonators with multiple frequencies of operation ranging between 5 and 10 GHz have been fabricated on the same chip and attained the highest f-Q product (4.6E12 Hz) ever reported in AlN contour-mode devices. These piezoelectric NEMS resonators are the first of their class to demonstrate on-chip sensing and actuation of nanostructures without the need of cumbersome or power consuming excitation and readout systems. Effective piezoelectric activity has been demonstrated in thin AlN films having vertical …


Nanoenabled Microelectromechanical Sensor For Volatile Organic Chemical Detection, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, A. T. Johnson, Gianluca Piazza Feb 2013

Nanoenabled Microelectromechanical Sensor For Volatile Organic Chemical Detection, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, A. T. Johnson, Gianluca Piazza

Matteo Rinaldi

A nanoenabled gravimetric chemical sensor prototype based on the large scale integration of single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNTs) as nanofunctionalization layer for aluminum nitride contour-mode resonant microelectromechanical (MEM) gravimetric sensors has been demonstrated. The capability of two distinct single strands of DNA bound to SWNTs to enhance differently the adsorption of volatile organic compounds such as dinitroluene (simulant for explosive vapor) and dymethyl-methylphosphonate (simulant for nerve agent sarin) has been verified experimentally. Different levels of sensitivity (17.3 and 28 KHz µm^2/fg) due to separate frequencies of operation (287 and 450 MHz) on the same die have also …


Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza Feb 2013

Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) superhigh- frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contourextensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5%. These devices are employed to …


Cause And Prevention Of Moisture-Induced Degradation Of Resistance Random Access Memory Nanodevices, Albert Chen Jan 2013

Cause And Prevention Of Moisture-Induced Degradation Of Resistance Random Access Memory Nanodevices, Albert Chen

Albert B Chen

Dielectric thin films in nanodevices may absorb moisture, leading to physical changes and property/performance degradation, such as altered data storage and readout in resistance random access memory. Here we demonstrate using a nanometallic memory that such degradation proceeds via nanoporosity, which facilitates water wetting in otherwise nonwetting dielectrics. Electric degradation only occurs when the device is in the charge-storage state, which provides a nanoscale dielectrophoretic force directing H2O to internal field centers (sites of trapped charge) to enable bond rupture and charged hydroxyl formation. While these processes are dramatically enhanced by an external DC or AC field and electron-donating electrodes, …


Integration Of Memristors With Mems For Dynamic Displacement Control, Sergio Fabian Almeida Loya Jan 2013

Integration Of Memristors With Mems For Dynamic Displacement Control, Sergio Fabian Almeida Loya

Open Access Theses & Dissertations

In recent years the demand for high-speed, lower power consumption and large-capacity non-volatile memories has increased. Promisingly the memristor can be used due to its special characteristic of having memory through resistance change. The memristor behavior is not limited to digital applications but it can be used in analog application as well including: memristors in chaotic circuits, amoeba's learning, neural synaptic emulation, reprogrammable and reconfigurable circuits, and for neuromorphic computers. On the other hand Micro Electro Mechanical Systems (MEMS) are small scale structures that can interact with the physical world due to their mechanical properties. These devices are widely used …


Properties Of Peg, Ppg And Their Copolymers Influence On The Gap-Fill Characteristics Of Damascene Interconnects, Kevin Ryan Jan 2013

Properties Of Peg, Ppg And Their Copolymers Influence On The Gap-Fill Characteristics Of Damascene Interconnects, Kevin Ryan

Legacy Theses & Dissertations (2009 - 2024)

A laboratory scale plating cell was built that provided reproducible bottom-up fill results for the electrochemical deposition of copper in damascene features. Several techniques used in the full wafer plating tool were incorporated into the setup to accurately control the process conditions. These techniques included but were not limited to a voltage controlled `hot-entry' step, a custom coupon holder to allow sample rotation, a secondary thief electrode and an automatic entry system. The results of qualification experiments are presented to demonstrate that precise control was realized along with repeatable partial fill plating results. The qualified setup was then used to …


Demonstration And Modeling Of Multi-Bit Resistance Random Access Memory, Albert Chen Dec 2012

Demonstration And Modeling Of Multi-Bit Resistance Random Access Memory, Albert Chen

Albert B Chen

Although intermediates resistance states are common in resistance random access memory (RRAM), two-way switching among them has not been demonstrated. Using a nanometallic bipolar RRAM, we have illustrated a general scheme for writing/rewriting multi-bit memory using voltage pulses. Stability conditions for accessing intermediate states have also been determined in terms of a state distribution function and the weight of serial load resistance. A multi-bit memory is shown to realize considerable space saving at a modest decrease of switching speed.