Steven DelaCruz

Graduate Student in Chemical and Biomolecular Engineering

Education

B. S. Chemical Engineering, University of Nevada – Reno (2015)

Current Research

Title: “Silicon carbide materials and processing”
Abstract: Due to their high mechanical robustness, thermal stability, chemical resilience, and breakdown field strength, silicon carbide (SiC)-based nanostructures can be broadly utilized in devices such as field emitters, supercapacitors, and gas sensors. While SiC nanostructures have been widely explored on rigid substrates, their integration on flexible substrates has been limited. Carbon cloth (CC) is an optimal substrate for direct SiC nanowire (NW) growth due to its high conductivity and melting point. My project seeks to investigate the growth of semi-aligned SiC NWs on CC via chemical vapor deposition. Evaluation of the as- deposited SiC NWs for select applications will be conducted and further modification of the SiC NWs/CC array will be investigated subsequently (e.g., using SiC NWs as backbones for developing application- targeted complex heterostructures or as precursors for carbide-derived carbon).

Completed Research

Title: “Silicon Carbide Passivated Electrode for Thermionic Energy Conversion”
Abstract: In thermionic energy converters (TECs), electrons emitted from a hot electrode (emitter) into a vacuum gap are harvested by a cooler electrode (collector), and then return to the emitter, delivering power to an external load. In this process, TECs convert heat directly into electricity and have the potential to achieve high efficiencies comparable to those of conventional heat engines. We have initiated a collaborative project to develop a microfabricated, close-gap thermionic energy converter that utilizes heat from a combustion source. Potential applications include residential combined heat and power systems and light-weight battery alternatives.

One key challenge is designing the emitter, which needs to be highly conductive and survive temperatures as hot as 1700 °C in an oxidizing environment. While tungsten is an attractive choice for the emitter, it readily oxidizes under the envisioned conditions. Owing to its chemical inertness and mechanical strength at high temperatures, silicon carbide is an effective option for electrode passivation. In this work, we are developing processes for fabricating a SiC- protected tungsten electrode, exploring the necessity and effectiveness of various interdiffusion barriers, and investigating its long-term stability under harsh environments.

Publications

  1. Zhongtao Wang, Steven DelaCruz, Dung-Sheng Tsai, Roya Maboudian, “W/TaC/SiC sandwich stack for high temperature applications,” Ceram Int, 2019
  2. Siyi Cheng, Steven DelaCruz, Chen Chen, Zirong Tang, Tielin Shi, Carlo Carraro, Roya Maboudian, “Hierarchical Co3O4/CuO nanorod array supported on carbon cloth for highly sensitive non-enzymatic glucose biosensing,” Sensor Actuat B-Chem, 2019, 298, 126860
  3. Siyi Cheng, Xiang Gao, Steven DelaCruz, Chen Chen, Zirong Tang, Tielin Shi, Carlo Carraro, Roya Maboudian, “In-situ formation of metal-organic framework derived CuO polyhedrons on carbon cloth for highly sensitive non-enzymatic glucose sensing,” J Mater Chem B, 2019
  4. Xiang Gao, Steven DelaCruz, Chenhui Zhu, Siyi Cheng, David Gardner, Yuhui Xie, Carlo Carraro, Roya Maboudian, “Surface functionalization of carbon cloth with cobalt-porphyrin-based metal organic framework for enhanced electrochemical sensing,” Carbon, 2019, 148, pp. 64-71
  5. Ping Cheng*, Steven DelaCruz*, Dung-Sheng Tsai, Zhongtao Wang, Carlo Carraro, Roya Maboudian. “Enhanced thermal stability by introducing TiN diffusion barrier layer between W and SiC,” J Am Ceram Soc, 2019, 102 (9), pp. 5613-5619
  6. Steven DelaCruz, Zhongtao Wang, Ping Cheng, Carlo Carraro, Roya Maboudian. “TiN diffusion barrier for stable W/SiC (0001) interfaces in inert ambient at high temperature,” Thin Solid Films, 2019, 670, pp. 54-59
  7. Chuan-Pei Lee, Lunet E Luna, Steven DelaCruz, Sinem Ortaboy, Francesca Rossi, Giancarlo Salviati, Carlo Carraro, Roya Maboudian. “Hierarchical cobalt oxide-functionalized silicon carbide nanowire array for efficient and robust oxygen evolution electro-catalysis,” Materials Today Energy, 2018, 7, pp. 37-43
  8. William Ragsdale, Satyajit Gupta, Keenan Conard, Steven DelaCruz, Vaidyanathan Ravi Subramanian. “Photocatalytic activity of Fe-modified bismuth titanate pyrochlores: Insights into its stability, photoelectrochemical, and optical responses,” Appl Catal B-Environ, 2016, 180, pp 442-450
  9. Josephine Selvarag, Satyajit Gupta, Steven DelaCruz, Vaidyanathan Subramanian. “Role of
    reduced graphene oxide in the critical components of a CdS-sensitized TiO2-based
    photoelectrochemical cell,” ChemPhysChem, 2014, 15 (10), pp 2010-2018
  10. Bradley Allured, Steven DelaCruz, Tiomthy Darling, Muhammad N Huda, Vaidyanathan Ravi Subramanian. “Enhancing the visible light absorbance of Bi2Ti2O7 through Fe-substitution and its effects on photocatalytic hydrogen evolution,” Appl Catal B-Environ, 2014, 144, pp 261-268

*Denotes equal contribution

Affiliations

Berkeley Sensor and Actuator Center (BSAC)
Lawrence Berkeley National Laboratory (LBNL): Molecular Foundry
Marvell NanoLab
Berkeley Biomolecular Nanotechnology Center

Awards/Honors

University of California Dissertation Year Fellowship Recipient
Tau Beta Pi Fellowship Recipient
Barry M. Goldwater Scholar
Morris K. Udall Scholar

Media Coverage

2015 Herz Gold Medalist
Honors on High

Teaching

Intro to Chemical Engineering, UC Berkeley, Fall 2015. Instructor: Dr. M. Went. Reviews:
Polymer Science and Technology, UC Berkeley, Fall 2016. Instructor: Dr. S. Muller. Review:
Process Technology of Solid-State Materials Devices, Fall 2018. Instructor: Dr. R. Maboudian. Review:

Contact

sdelacruz@berkeley.edu