Kim, Gyuseok
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Publication Make and Characterize Microfluidic Devices with Gelatin: Do-it-yourself (DIY) Laboratory at Home(Singh Center for Nanotechnology, 2021-11-09) Youderian, Marissa; Song, Xilai; Lancaster, Mark; Jones, David J.; Jhamb, Ahana; Kim, Gyuseok L.Microfluidic devices have been fabricated with gelatin and paper clips. Optimization of fabrication and characterization process has been carried out systemically by varying gelatin-to-water ratio, bonding time and connector type. We find that the higher gelatin-to-water ratio and the luer lock syringe tip provide a greater success rate, whereas the influence of bonding time is limited. The Reynolds number was calculated to identify whether the fluid shows laminar or turbulent flow.Publication Electrical Characterization of Solar Cell using Arduino and Polarization Film(Singh Center for Nanotechnology, 2022-08-24) Lancaster, Mark; Jhamb, Ahana; Song, Xilai; Unger, Gabriel; Youderian, Marissa; Kim, Gyuseok L.A solar cell laboratory course for high school and college undergraduate students is proposed. The electrical characterization of the solar cell is performed to confirm the functionality of the device as both a diode and a power source. The efficiency of the solar cell in the illuminated condition is found to be 13.1 %. We find the efficiency of the solar cell slightly decreases as the intensity of light decreases. However, there is no significant difference in efficiency except for in the opaque condition. A calibrated solar cell, multimeter, current sensor, Arduino, coding and polarization are used to perform the experiment.Publication Exploring Hydrophobic and Lipophilic Properties of Magic Sand: Implications for Oil Spill Cleanup(Singh Center for Nanotechnology) Unger, Gabriel; Song, Ethan; Kim, GyuseokIn this study, we investigate the hydrophobic and lipophilic properties of magic sand by examining the behavior of water and oil droplets on magic sand surfaces. The contact angle between water and magic sand exceeds 120 degrees, indicating hydrophobic behavior, while the contact angle between oil and magic sand is significantly less than 90 degrees, suggesting lipophilic characteristics. To establish a comparative analysis, we performed similar tests using regular sand, demonstrating hydrophilic and lipophilic properties with contact angles against water and oil of less than 90 degrees. Leveraging these divergent properties, we conducted a simulated oil spill cleanup employing magic sand, resulting in a notable reduction of oil levels in water as the magic sand readily absorbed and sank with the oil.Publication Characterization and Optimization of Parylene-C deposition process using SCS Parylene coater(2019-01-15) Hastings, Hannah; Johnston, Eric D; Kim, GyuseokParylene-C has been deposited on bare Si wafers by physical vapor deposition using the SCS Coating Systems. Results show a 12 µm thick Parylene-C film with 10 g of dimer and negligible thickness variation across a wafer. We find a positive linear relationship between film thickness and mass of dimer at a range of 1 g to 18 g. However, the Al boat for dimer was burnt with 18 g of dimer, suggesting multiple depositions with 1 g to 10 g of dimer are recommended to achieve the Parylene-C film thicker than 12 µm.Publication Influence of flow rate, nozzle speed, pitch and the number of passes on the thickness of S1805 photoresist in SUSS MicroTec AS8 spray coater(2019-10-15) Sanghvi, Rohan; Kim, GyuseokS1805 positive photoresist has been deposited on single crystalline Si wafers using a Suss MicroTec Alta Spray. The influence of flow rate, nozzle speed, pitch and number of passes on the thickness of the photoresist was studied. Results show that the thickness of S1805 is linearly proportional to the flow rate and number of passes, and inversely proportional to the nozzle speed and pitch.Publication How to Make Chips with Nanofabrication | University of Pennsylvania(2020-11-10) Hoang, Lauren; Idris, Abbas; Farnan, Dale; Macera, Felice; Wallace, Ashely; Jones, David; Kim, GyuseokThe Singh Center for Nanotechnology and LRSM at the University of Pennsylvania demonstrate the nanofabrication process to make chips using lithography, deposition and etch. Fabricated chips were characterized with reflectometry and opticalmicroscopy. For more information: https://www.nano.upenn.edu/ https://www.nnci.net/Publication CdSe Quantum Dots Synthesis Laboratory Course for High School Students(2019-12-06) Zuo, Danlin; Kim, Gyuseok; Jones, DavidCadmium selenide quantum dot is a fascinating subject for leading high school students to the quantum world. An 8-hour laboratory course for up to 12 high school students is proposed. The 8-hour course consist of two 4-hours sections. This laboratory course includes the quantum dot syntheses, absorption and emission characterization, and data analysis. The proposes process runs at relatively lower temperature which means safe and easy, and shows apparent experimental results.Publication Optimization of Ultrasonic Aluminum Wire Bonding on Chromium and Gold Surfaces Using K&S Wedge Wire Bonder(2019-10-25) Tetro, Ryan; Kim, GyuseokUltrasonic wire bonding of aluminum wire has been carried out onto gold and chromium surfaces using K&S wedge wire bonder (Model: 4523). Three distinct settings, power, time, and force were varied to find and propose the optimal process parameters for strong mechanical and electrical bond between the Al wire and the Cr and Au surfaces. It turned out that the range of optimal process windows for bonding onto a Cr surface is much smaller than bonding onto an Au surface. The range of power, time, and force for Cr are 3.0 - 3.5, 3.0 - 5.0, and 2.0 - 3.0 ± 1.0, respectively. To the contrary, the range of power, time, and force for Au are 2.5 - 4.0, 4.0 - 5.0 ± 1.0, and 3.0 - 4.0 ± 1.0, respectively.Publication MEMS Device Demonstration for High School Students or Nonspecialists(2021-10-28) Kim, Gyuseok L.; Meng, Jeffrey; Unger, GabrielMicro-electromechanical systems (MEMS) devices have many unique advantages, and offer an exciting entrance for students into the field of nanotechnology and nanofabrication. In this article, an educational hands-on laboratory protocol with MEMS devices is proposed. Using a paper airplane, an Arduino, and the MPU 6050 MEMS accelerometer/gyroscope sensor students are able to create a graphical aircraft attitude indicator. The data is then processed on the Arduino, which is connected to a computer. The computer can then run graphics software displaying a digital aircraft attitude indicator showing the roll and pitch of the aircraft live.