Matching Items (6)
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- All Subjects: fabrication
- Creators: Engineering Programs
- Creators: Chandra, Nishant
- Creators: Farber-Schaefer, Blaine
Description
Semiconductor nanowires are important candidates for highly scaled three dimensional electronic devices. It is very advantageous to combine their scaling capability with the high yield of planar CMOS technology by integrating nanowire devices into planar circuits. The purpose of this research is to identify the challenges associated with the fabrication of vertically oriented Si and Ge nanowire diodes and modeling their electrical behavior so that they can be utilized to create unique three dimensional architectures that can boost the scaling of electronic devices into the next generation. In this study, vertical Ge and Si nanowire Schottky diodes have been fabricated using bottom-up vapor-liquid-solid (VLS) and top-down reactive ion etching (RIE) approaches respectively. VLS growth yields nanowires with atomically smooth sidewalls at sub-50 nm diameters but suffers from the problem that the doping increases radially outwards from the core of the devices. RIE is much faster than VLS and does not suffer from the problem of non-uniform doping. However, it yields nanowires with rougher sidewalls and gets exceedingly inefficient in yielding vertical nanowires for diameters below 50 nm. The I-V characteristics of both Ge and Si nanowire diodes cannot be adequately fit by the thermionic emission model. Annealing in forming gas which passivates dangling bonds on the nanowire surface is shown to have a considerable impact on the current through the Si nanowire diodes indicating that fixed charges and traps on the surface of the devices play a major role in determining their electrical behavior. Also, due to the vertical geometry of the nanowire diodes, electric field lines originating from the metal and terminating on their sidewalls can directly modulate their conductivity. Both these effects have to be included in the model aimed at predicting the current through vertical nanowire diodes. This study shows that the current through vertical nanowire diodes cannot be predicted accurately using the thermionic emission model which is suitable for planar devices and identifies the factors needed to build a comprehensive analytical model for predicting the current through vertically oriented nanowire diodes.
ContributorsChandra, Nishant (Author) / Goodnick, Stephen M (Thesis advisor) / Tracy, Clarence J. (Committee member) / Yu, Hongbin (Committee member) / Ferry, David K. (Committee member) / Arizona State University (Publisher)
Created2014
Description
Three dimensional printing is a growing field and an excellent medium for rapid prototyping. Its expansion has accelerated over recent years due to the increased affordability of the technology. It is now at the point where the startup cost to get into the field is down to the hobbyist price point. This means that there is an extremely high demand for affordable printing media. Current media such as ABS and PLA is extremely easy to form, but expensive and petroleum intensive to create. A recycling system that could work with a large variety of waste products could change the way that the maker community recycles. This Honors Thesis, or "Creative Project" will be centered on the product launch of small business 3DCycler. Although this launch will require pulling information and skills from various branches of both Business and Science, the scope of this project will be limited to specifically the market entrance of our small business/ product. Within this blanket goal, the project aims to define our target market/ its niche(s), develop proper IP/ lockout strategies, define future manufacturing strategies, and to fully define our beta product. The research was empirical in nature. Through data gathering techniques (e.g., consultations, interviews, survey), exploration was performed. Through these techniques the company 3DCycler took several calculated pivots in order to prepare the company for a strategic product launch and eventual acquisition.
ContributorsFarber-Schaefer, Blaine (Author) / Cho, Steve (Thesis director) / Goodman, Tom (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
ContributorsAcevedo, Rodrigo (Author, Co-author) / Rajadas, John (Thesis director) / Nam, Changho (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2021-12
ContributorsAcevedo, Rodrigo (Author, Co-author) / Rajadas, John (Thesis director) / Nam, Changho (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2021-12
Description
After the wind tunnels in the SIM building and Innovation Hub were donated or lost, Dr. Rajadas requested a new wind tunnel be designed, developed, and fabricated using facilities and resources available on ASU Polytech. Over 6 months, a single student was tasked with running the CAD modeling process, undergoing the revision stages, and welding/fabricating the tunnel by the end of Fall 2021.
ContributorsAcevedo, Rodrigo (Author, Co-author) / Rajadas, John (Thesis director) / Nam, Changho (Committee member) / Barrett, The Honors College (Contributor) / Engineering Programs (Contributor)
Created2021-12
Description
For the basis of this project, a particular interest is taken in soft robotic arms for the assistance of daily living tasks. A detailed overview and function of the soft robotic modules comprised within the soft robotic arm will be the main focus. In this thesis, design and fabrication methods of fabric reinforced textile actuators (FRTAs) have their design expanded. Original design changes to the actuators that improve their performance are detailed in this report. This report also includes an explanation of how the FRTA’s are made, explaining step by step how to make each sub-assembly and explain its function. Comparisons between the presented module and the function of the soft poly limb from previous works are also expanded. Various forms of testing, such as force testing, range of motion testing, and stiffness testing are conducted on the soft robotic module to provide insights into its performance and characteristics. Lastly, present plans for various forms of future work and integration of the soft robotic module into a full soft robotic arm assembly are discussed.
ContributorsSeidel, Sam (Author) / Zhang, Wenlong (Thesis director) / Sugar, Thomas (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05