More Like this

1. CO ₂ and HDPE Upcycling: A Plasma Catalysis Alternative

   https://doi.org/10.1021/acs.iecr.3c02403  

   Gorky, Fnu; Nambo, Apolo; Kessler, Travis J; Mack, J Hunter; Carreon, Maria L (November 2023, Industrial & Engineering Chemistry Research)
2. Effects of Downstream Plasma Exposure on β-Ga ₂ O ₃ Rectifiers

   https://doi.org/10.1149/2162-8777/ac0500  

   Xia, Xinyi; Xian, Minghan; Fares, Chaker; Ren, Fan; Kim, Junghun; Kim, Jihyun; Tadjer, Marko; Pearton, Stephen J. (June 2021, ECS Journal of Solid State Science and Technology)

   The effects of downstream plasma exposure with O 2 , N 2 or CF 4 discharges on Si-doped Ga 2 O 3 Schottky diode forward and reverse current-voltage characteristics were investigated. The samples were exposed to discharges with rf power of 50 W plasma at a pressure of 400 mTorr and a fixed treatment time of 1 min to simulate dielectric layer removal, photoresist ashing or surface cleaning steps. Schottky contacts were deposited through a shadow mask after exposure to avoid any changes to the surface. A Schottky barrier height of 1.1 eV was obtained for the reference sample without plasma treatment, with an ideality factor of 1.0. The diodes exposed to CF 4 showed a 0.25 V shift from the I–V of the reference sample due to a Schottky barrier height lowering around 14%. The diodes showed a decrease of Schottky barrier height of 2.5 and 6.5% with O 2 or N 2 treatments, respectively. The effect of plasma exposure on the ideality factor of diodes treated with these plasmas was minimal; 0.2% for O 2 and N 2 , 0.3% for CF 4 , respectively. The reverse leakage currents were 1.2, 2.2 and 4.8 μ A cm −2 for the diodes treated with O 2 , and CF 4 , and N 2 respectively. The effect of downstream plasma treatment on diode on-resistance and on-off ratio were also minimal. The changes observed are much less than caused by exposure to hydrogen-containing plasmas and indicate that downstream plasma stripping of films from Ga 2 O 3 during device processing is a relatively benign approach. 

   more » « less
3. Predicting plasma conditions necessary for synthesis of γ-Al ₂ O ₃ nanocrystals

   https://doi.org/10.1039/d1nr02488d  

   Cendejas, Austin J.; Sun, He; Hayes, Sophia E.; Kortshagen, Uwe; Thimsen, Elijah (July 2021, Nanoscale)

   null (Ed.)

   Nonthermal plasma (NTP) offers a unique synthesis environment capable of producing nanocrystals of high melting point materials at relatively low gas temperatures. Despite the rapidly growing material library accessible through NTP synthesis, designing processes for new materials is predominantly empirically driven. Here, we report on the synthesis of both amorphous alumina and γ-Al 2 O 3 nanocrystals and present a simple particle heating model that is suitable for predicting the plasma power necessary for crystallization. The heating model only requires the composition, temperature, and pressure of the background gas along with the reactor geometry to calculate the temperature of particles suspended in the plasma as a function of applied power. Complete crystallization of the nanoparticle population was observed when applied power was greater than the threshold where the calculated particle temperature is equal to the crystallization temperature of amorphous alumina. 

   more » « less
4. Contact Engineering for Dual-Gate MoS ₂ Transistors Using O ₂ Plasma Exposure

   https://doi.org/10.1021/acsaelm.8b00059  

   Bolshakov, Pavel; Smyth, Christopher M.; Khosravi, Ava; Zhao, Peng; Hurley, Paul K.; Hinkle, Christopher L.; Wallace, Robert M.; Young, Chadwin D. (January 2019, ACS Applied Electronic Materials)
5. Plasma-jet printing of colloidal thermoelectric Bi ₂ Te ₃ nanoflakes for flexible energy harvesting

   https://doi.org/10.1039/d2nr06454e  

   Manzi, Jacob; Weltner, Ariel E.; Varghese, Tony; McKibben, Nicholas; Busuladzic-Begic, Mia; Estrada, David; Subbaraman, Harish (April 2023, Nanoscale)

   Thermoelectric generators (TEGs) convert temperature differences into electrical power and are attractive among energy harvesting devices due to their autonomous and silent operation. While thermoelectric materials have undergone substantial improvements in material properties, a reliable and cost-effective fabrication method suitable for microgravity and space applications remains a challenge, particularly as commercial space flight and extended crewed space missions increase in frequency. This paper demonstrates the use of plasma-jet printing (PJP), a gravity-independent, electromagnetic field-assisted printing technology, to deposit colloidal thermoelectric nanoflakes with engineered nanopores onto flexible substrates at room temperature. We observe substantial improvements in material adhesion and flexibility with less than 2% and 11% variation in performance after 10 000 bending cycles over 25 mm and 8 mm radii of curvature, respectively, as compared to previously reported TE films. Our printed films demonstrate electrical conductivity of 2.5 × 10 3 S m −1 and a power factor of 70 μW m −1 K −2 at room temperature. To our knowledge, these are the first reported values of plasma-jet printed thermoelectric nanomaterial films. This advancement in plasma jet printing significantly promotes the development of nanoengineered 2D and layered materials not only for energy harvesting but also for the development of large-scale flexible electronics and sensors for both space and commercial applications. 

   more » « less