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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Carbon Removal And Optoelectronic Property Tuning In Copper Arsenic Sulfide Thin Films Through Ligand Exchange And Alloying, Louis R. Schroeder, Scott Mcclary, Rakesh Agrawal
Carbon Removal And Optoelectronic Property Tuning In Copper Arsenic Sulfide Thin Films Through Ligand Exchange And Alloying, Louis R. Schroeder, Scott Mcclary, Rakesh Agrawal
The Summer Undergraduate Research Fellowship (SURF) Symposium
Solution processed thin film solar cells are attractive alternatives to conventional energy sources due to low waste generation, flexibility in substrate choice, and scalability. The novel semiconductor Cu3AsS4 in the enargite phase has a near ideal band gap of 1.4 eV and has earth abundant constituent elements; yet single-junction solar cells have yielded low efficiencies due to a secondary carbonaceous phase present, among other issues. This carbonaceous phase may be eliminated by exchanging the carbonaceous ligands with molecular metal chalcogenides. To characterize the ligand exchanged particles, UV-Vis-NIR spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and …
Improving Methods Of Doping On Black Phosphorus, Yuqin Duan, Adam Charnas, Jingkai Qin, Peide Ye
Improving Methods Of Doping On Black Phosphorus, Yuqin Duan, Adam Charnas, Jingkai Qin, Peide Ye
The Summer Undergraduate Research Fellowship (SURF) Symposium
Black phosphorus (BP) is a 2D semiconducting material with high carrier mobility. It is usually p-type due to oxidation states near its valence band. Although achieved through other growth methods, n-type doping has not yet been accomplished through the modern chemical vapor transport (CVT) growth method. To address this issue, small amounts of tellurium were added to Red Phosphorus to act as a dopant during the CVT growth process in addition to tin(Sn) and tin(IV) iodide, which facilitate growth. The chemicals are heated up to 600°C and precisely cooled in a 21-hour process, during which BP crystals should form. After …
Virtual-Source Based Accurate Model For Predicting Noise Behavior At High Frequencies In Nanoscale Pmos Soi Transistors, Vaibhav R. Ramachandran, Saeed Mohammadi, Sutton Hathorn
Virtual-Source Based Accurate Model For Predicting Noise Behavior At High Frequencies In Nanoscale Pmos Soi Transistors, Vaibhav R. Ramachandran, Saeed Mohammadi, Sutton Hathorn
The Summer Undergraduate Research Fellowship (SURF) Symposium
Complementary Metal Oxide Semiconductor (CMOS) technology at the nanometre scale is an excellent platform to implement monolithically integratedsystems because of the low cost of manufacturing and ease of integration. Newly developed CMOS Silicon on Insulator (SOI) transistors that are currentlydeveloped are suitable for use in radio frequency circuits. They find applications in many areas such as 5G telecommunication systems, high speed Wi-Fi andairport body-scanners. Unfortunately, the models for CMOS SOI transistors that are currently used in these circuits are inaccurate because of their complexity.The models currently used require the optimization of more than 200 variables. This paper aims to accurately …
Atomistic Configuration Interaction Simulation Tool For Semiconductor Based Quantum Computing Devices, Jingbo Wu, Archana Tankasala, Jim Fonseca, Rajib Rahman, Gerhard Klimeck
Atomistic Configuration Interaction Simulation Tool For Semiconductor Based Quantum Computing Devices, Jingbo Wu, Archana Tankasala, Jim Fonseca, Rajib Rahman, Gerhard Klimeck
The Summer Undergraduate Research Fellowship (SURF) Symposium
Solid-state devices are promising candidates for quantum computing applications due to obvious advantages in compatibility with semiconductor fabrication technologies and the extremely long coherent times of electron and nuclear spins in these devices. In such devices, electron interactions are crucial for single and two qubit gate operations. Thus it is essential to evaluate these electron-electron interactions accurately for precise qubit control. It is shown that Atomistic Configuration Interaction can be used to accurately determine electron-electron interactions in realistic semiconductor quantum computing devices. In this work, an online simulation tool on Atomistic Configuration Interaction has been implemented and published on nanoHUB.org, …
Wearable Piezotronic Devices For Heart Rate Monitoring, Adam J. Miller, Wenzhuo Wu Dr.
Wearable Piezotronic Devices For Heart Rate Monitoring, Adam J. Miller, Wenzhuo Wu Dr.
The Summer Undergraduate Research Fellowship (SURF) Symposium
Self-powered multifunctional wearable devices that are capable of human-device interfacing are highly desired. Piezotronic devices utilize piezoelectricity and semiconductor properties to enable devices to have seamless interaction between human and device. One important use for piezotronic devices is for pressure sensing. Pressure sensing devices have been employed in smart skins, biomonitoring, gesture recognition, and many more applications. This study aims to create a flexible piezotronic device, specifically for use in pressure sensing to monitor heart rate. ZnO nanowires are grown on a flexible polymer substrate so that they can be made into wearable devices. A p-n heterojunction is formed by …
Reward Modulated Spike Timing Dependent Plasticity Based Learning Mechanism In Spiking Neural Networks, Shrihari Sridharan, Gopalakrishnan Srinivasan, Kaushik Roy
Reward Modulated Spike Timing Dependent Plasticity Based Learning Mechanism In Spiking Neural Networks, Shrihari Sridharan, Gopalakrishnan Srinivasan, Kaushik Roy
The Summer Undergraduate Research Fellowship (SURF) Symposium
Spiking Neural Networks (SNNs) are one of the recent advances in machine learning that aim to further emulate the computations performed in the human brain. The efficiency of such networks stems from the fact that information is encoded as spikes, which is a paradigm shift from the computing model of the traditional neural networks. Spike Timing Dependent Plasticity (STDP), wherein the synaptic weights interconnecting the neurons are modulated based on a pair of pre- and post-synaptic spikes is widely used to achieve synaptic learning. The learning mechanism is extremely sensitive to the parameters governing the neuron dynamics, the extent of …
Mechanical Reliability Of Implantable Polyimide-Based Magnetic Microactuators For Biofouling Removal, Christian G. Figueroa-Espada, Qi Yang, Hyowon Lee
Mechanical Reliability Of Implantable Polyimide-Based Magnetic Microactuators For Biofouling Removal, Christian G. Figueroa-Espada, Qi Yang, Hyowon Lee
The Summer Undergraduate Research Fellowship (SURF) Symposium
Hydrocephalus is a neurological disorder that typically requires a long-term implantation of a shunt system to manage its symptoms. These shunt systems are notorious for their extremely high failure rate. More than 40% of all implanted shunt systems fail within the first year of implantation. On average, 85% of all hydrocephalus patients with shunt systems undergo at least two shunt-revision surgeries within 10 years of implantation. A large portion of this high failure rate can be attributed to biofouling-related obstructions and infections. Previously, we developed flexible polyimide-based magnetic microactuators to remove obstructions formed on hydrocephalus shunts. To test the long-term …
Mass-Positioning Of Nanodiamonds Using Squeegee Technique, Ran Cui, Mikhail Y. Shalaginov, Vladimir M. Shalaev
Mass-Positioning Of Nanodiamonds Using Squeegee Technique, Ran Cui, Mikhail Y. Shalaginov, Vladimir M. Shalaev
The Summer Undergraduate Research Fellowship (SURF) Symposium
Fluorescent color centers in diamond nanocrystals have recently become the focus of researchers because of their potential applications in quantum information processing, nano-sensing, biomarking, and bioimaging. One of the biggest challenges in working with nanodiamonds is how to position them precisely and efficiently to create strong interaction with nanoscale photonic structures. The most popular methods to position nanodiamonds are spin-coating and transporting via scanning probe microscope tip. On the one hand, spin-coating, where nanodiamonds are randomly located, is not precise; on the other hand, the tip-based technique, where a single nanodiamond is picked and dropped, is tedious and time-consuming. Hence, …
Simulating Nanowires And Ultra-Thin Body Transistors Using Nemo5 On Nanohub.Org, Liang Yuan Dai, James E. Fonseca, Chu Yuan Chen, Gerhard Klimeck
Simulating Nanowires And Ultra-Thin Body Transistors Using Nemo5 On Nanohub.Org, Liang Yuan Dai, James E. Fonseca, Chu Yuan Chen, Gerhard Klimeck
The Summer Undergraduate Research Fellowship (SURF) Symposium
During the past twenty years, the most important aspects of semiconductor electronics have advanced into the nanometer range, resulting in exponential increases of microprocessor computing performance. As the size of electrical components continues to shrink, the cost of experimental research and industrial fabrication in this field has increased dramatically. Thus, the development of accurate nanoscale model simulations becomes necessary as a measure to decrease the high financial expenses of advancing semiconductor technology. This simulator supports atomistic modeling in order to provide an accurate description of the nanoscale devices, as current electrical components operate in the quantum regime and are affected …
Simplified Generation Of The Input Models Of Object Oriented Micromagnetic Framework (Oommf), Jinyang Yu, Rafatul Faria, Supriyo Datta, Tanya A. Faltens
Simplified Generation Of The Input Models Of Object Oriented Micromagnetic Framework (Oommf), Jinyang Yu, Rafatul Faria, Supriyo Datta, Tanya A. Faltens
The Summer Undergraduate Research Fellowship (SURF) Symposium
Object Oriented MicroMagnetic Framework (OOMMF) is a micromagnetic simulation tool. It takes a memory initialization file (MIF) as the input and outputs various forms of data such as data table, graph and magnetic configuration plots. It is accurate and fast compared to other existing tools such as MATLAB. Few experimentalists used it in the past, however, due to two main reasons. First, OOMMF requires a specific version of programming environment on the local computer which is difficult to be installed. Second, MIF file is very complicated to code and it also requires users to read a lengthy guidelines. Our solution …
Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu
Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu
The Summer Undergraduate Research Fellowship (SURF) Symposium
Atomically thin black phosphorus (phosphorene) has both unique and desirable properties that differ from bulk black phosphorus. Unlike graphene, phosphorene has a bandgap, which makes it potentially useful for applications in the next generation of transistors. Large-scale applications of phosphorene, like other 2D materials, are limited by current production methods. The most common method of making phosphorene is mechanical exfoliation, which can only produce small and irregular quantities. In this work we investigate a top-down method of producing phosphorene by using a scanning ultrafast laser to thin black phosphorus flakes. Because the bandgap of phosphorene increases as layers are removed, …
Modeling Thermophotovoltaic Rare Earth Based Selective Emitters, Anubha Mathur, Enas Said Sakr, Peter Bermel
Modeling Thermophotovoltaic Rare Earth Based Selective Emitters, Anubha Mathur, Enas Said Sakr, Peter Bermel
The Summer Undergraduate Research Fellowship (SURF) Symposium
Thermophotovoltaic (TPV) devices convert heat to electricity using thermal radiation to illuminate a photovoltaic (PV) diode. Typically, this radiation is generated by a blackbody-like emitter. Such an emission spectrum includes a broad range of wavelengths, but only higher energy photons can be converted by the PV diode, which severely limits efficiencies. Thus, introducing a selective emitter and filter to recycle unwanted photons could potentially greatly enhance performance. In this work, we consider a rare earth-doped selective emitter structure to increase the number of photons emitted above the bandgap of the photovoltaic (PV) cell, while minimizing the total power emitted below …
Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan
Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan
The Summer Undergraduate Research Fellowship (SURF) Symposium
Density Functional Theory (DFT) simulations allow for sophisticated modeling of chemical interactions, but the extreme computational cost makes it inviable for large scale applications. Molecular dynamics models, specifically ReaxFF, can model much larger simulations with greater speed, but with lesser accuracy. The accuracy of ReaxFF can be improved by comparing predictions of both methods and tuning ReaxFF’s parameters. Molecular capabilities of ReaxFF were gauged by simulating copper complexes in water over a 200 ps range, and comparing energy predictions against ReaxFF. To gauge solid state capabilities, volumetric strain was applied to simulated copper bulk and the strain response functions used …
Finite-Difference Time-Domain Simulation Of Photovoltaic Structures Using A Graphical User Interface For Meep, Xin Tze Tee, Peter Bermel
Finite-Difference Time-Domain Simulation Of Photovoltaic Structures Using A Graphical User Interface For Meep, Xin Tze Tee, Peter Bermel
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is a large and growing need for accurate full-wave optical simulations of complex systems such as photovoltaic (PV) cells, particularly at the nanoscale. A finite-difference time-domain tool known as MEEP offers this capability in principle, through C++ libraries and the Scheme programming language. For expert users, this approach has been quite successful, but there is also great interest from new and less frequent users in starting to use MEEP. In order to facilitate this process, we have developed a graphical user interface (GUI) for MEEP, geared toward simulation of 2D and 3D PV cell geometries, freely available through a …
Mems Lab Simulation Tool, Oluwatosin D. Adeosun, Sambit Palit, Ankit Jain, Muhammad A. Alam
Mems Lab Simulation Tool, Oluwatosin D. Adeosun, Sambit Palit, Ankit Jain, Muhammad A. Alam
The Summer Undergraduate Research Fellowship (SURF) Symposium
MEMS actuators have multiple design applications. Understanding their behavior as well as the ability to predict their actuation characteristics and voltage response is important when designing these actuators. In order to know these devices will behave, designers have to solve multiple analytical equations and experiments that can be very time consuming. Over the course of the summer a tool was created on nanoHUB that will allow users to enter information about a MEMS actuator and provide the voltage response of the actuator. To create the tool, scaling equations were first provided for various geometry configurations and the equations were next …
Stanford Stratified Structure Solver (S4) Simulation Tool, Chang Liu, Xufeng Wang, Peter Bermel
Stanford Stratified Structure Solver (S4) Simulation Tool, Chang Liu, Xufeng Wang, Peter Bermel
The Summer Undergraduate Research Fellowship (SURF) Symposium
The Stanford Stratified Structure Solver (S4) developed in 2012 allows for fast, accurate prediction of optical propagation through complex 3D structures. However, there have been two key challenges preventing wider use to date: the use of a specialized control language, and the difficulty of incorporating realistic materials parameters. In this project, both concerns have been addressed. We have constructed a graphical user interface as an alternative, using the open-source Rappture platform on nanoHUB. This has been combined with a comprehensive materials database known as PhotonicsDB, which incorporates materials optical data drawn from carefully vetted sources. An Octave script file was …
Thermophotovoltaic System Efficiency Simulation, Qingshuang Chen, Roman Shugayev, Peter Bermel
Thermophotovoltaic System Efficiency Simulation, Qingshuang Chen, Roman Shugayev, Peter Bermel
The Summer Undergraduate Research Fellowship (SURF) Symposium
Thermophotovoltaic (TPV) power systems, which convert heat into electricity using a photovoltaic diode to collect thermal radiation, have attracted increasing attention in recent work. It has recently been proposed that new optical structures such as photonic crystals can significantly improve the efficiency of these devices in two ways. First, the electronic bandgap of the TPV diode should match the photonic bandgap of the emitter, in order to ensure that the majority of emitted photons can be converted. Second, a photonic crystal short-pass optical filter can be added to the front of the TPV diode to send long wavelength photons back …