Book Chapters

  1. DiGregorio, S; Hildreth, O*; Particle-less Reactive Inks; Gupta, R; Nguyen, T; Eds: Smart Multifunctional Nano-Inks: Fundamentals and Emerging Applications; Elsevier; 2022, In Press

  2. Hildreth, O.; Wong, C. P.; Li, L. Applications of Metal-Assisted Chemical Etching in Microelectronics Packaging; Materials for Advanced Packaging, Springer, Boston, 2016, 879-992
  3. Lin, W.; Hildreth, O.; Wong, C. P.; Carbon Nanotubes as Thermal Interface Materials for Electronic and Photonic Packaging; Bernd, M.; Reichl, H., Eds.; Smart System Integration and Reliability; Boldernbogen: Dresden, 2010, 56-67

Refereed Journal Publications

  1. Raikar, S.; DiGregorio, S.; Agnani, M.; Hommer, G.; Hildreth, O.* Improving Fatigue Performance of Additively Manufactured Ti-6Al-4V Using Sulfur-Based Self-Terminating Etching Processes, Additive Manufacturing, In press, accepted Nov. 2022
  2. DiGregorio, S.; Hildreth, O.; Walker, L.; All-atmospheric Processed Ag-Cu Core-Shell Nanowire Transparent Electrode with Haacke Figure of Merit >600. Scientific Reports 2022, 12, 20962, 1-9, doi: 10.1038/s41598-022-25080-x
  3. Prochaska, S; Walker, M.; Hildreth, O.* Effect of Microstructure and Dislocation Density on Material Removal and Surface Finish of Laser Powder Bed Fusion 316L Stainless Steel Subject to a Self-Terminating Etching Process. 3D Printing and Additive Manufacturing, In press, Accepted 2022, doi: 10.1089/3dp.2022.0190
  4. Yazdanparast, S.; Raikar, S.; Heilig, M.; and Hildreth, O. Iodine-Based Sensitization of Copper Alloys to Enable Self-Terminating Etching for Support Removal and Surface Improvements of Additively Manufactured Components; 3D Printing and Additive Manufacturing, In Press, 2022
  5. Prochaska, S.; and Hildreth, O.* Microstructural and corrosion effects of HIP and chemically accelerated surface finishing on laser powder bed fusion Alloy 625. International Journal of Advanced Manufacturing Technology, 2022, 1–11
  6. Prochaska, S.; and Hildreth, O. Effect of Chemically Accelerated Vibratory Finishing on the Corrosion Behavior of Laser Powder Bed Fusion 316 L Stainless Steel. Journal of Materials Processing Technology, 2022, 117596
  7. Thomas, S., Yazdanparast, S., Hildreth, O.; and Zaeem, M. A. Formation energies, electronic properties and elemental diffusion of Cu–Cr–Nb (GRCop) alloys. Phys B Condensed Matter, 2022, 413909
  8. Thomas, S., Hildreth, O.; and Zaeem, M. A. Unveiling the effect of vacancy defects on structural, mechanical, electronic and diffusion properties of copper (I) iodide. Scripta Materiala, 2022, 213, 114634
  9. Raikar, S.; Heilig, M.; Mamidanna, A.; Hildreth, O. Self-Terminating Etching Process for Automated Support Removal and Surface Finishing of Additively Manufactured Ti-6Al-4V. Additive Manufacturing, 2021, 37, 1-8
  10. Hoffman, R.; Hinnebusch, S.; Raikar, S.; To, A. C.; Hildreth, O. Support Thickness, Pitch, and Applied Bias Effects on the Carbide Formation, Surface Roughness, and Material Removal of Additively Manufactured 316 L Stainless Steel. Journal of Materials, 2020, 27, 1–10
  11. Thomas, S.; Hildreth, O.; Asle Zaeem, M. Unveiling the Role of Atomic Defects on the Electronic, Mechanical and Elemental Diffusion Properties in CuS. Scripta Materialia; 2020, 192, 94–99.
  12. Lefky, C. S.; Gallmeyer, T. G.; Moorthy, S.; Stebner, A.; Hildreth, O. Microstructure and Corrosion Properties of Sensitized Laser Powder Bed Fusion Printed Inconel 718 to Dissolve Support Structures in a Self-Terminating Manner. Additive Manufacturing 2019, 27, 526–532.
  13. Lefky, C. S.; Mamidanna, A.; Hildreth, O. Ultra Near-Field Electrohydrodynamic Cone-Jet Breakup of Self-Reducing Silver Inks. J Electrostat; 2018, 96, 85–89.
  14. Mamidanna, A.; Jeffries, A.; Bertoni, M.; Hildreth, O. Adhesion of Reactive Silver Inks on Indium Tin Oxide. Journal of Materials Science 2018, 9, 1–10.
  15. Lefky, C. S.; Zucker, B.#; Nassar, A. R.; Simpson, T. W.; Hildreth, O. Impact of Compositional Gradients on Selectivity of Dissolvable Support Structures for Directed Energy Deposited Metals. Acta Materialia 2018, 153, 1–7.

  16. Mamidanna, A.; Lefky, C. S.; Hildreth, O. Drop-on-Demand Printed Microfluidics Device with Sensing Electrodes Using Silver and PDMS Reactive Inks. Microfluid Nanofluid 2017, 21, R15.

  17. Lefky, C. S.; Zucker, B. Nassar, A. R.; Simpson, T. W.; Hildreth, O. Dissolvable Supports in Powder Bed Fusion Printed Stainless Steel. 3D Print. Addit. Manuf. 2017, 4, 3-11.
  18. Jeffries, A. M.; Mamidanna, A.; Ding, L.; Hildreth, O.; Bertoni, M. I. Low-Temperature Drop-on-Demand Reactive Silver Inks for Solar Cell Front-Grid Metallization. IEEE Journal of Photovoltaics 2017, 7, 37–43.
  19. Zhao, Z.; Mamidanna, A.; Lefky, C. S.; Hildreth, O.; Alford, T. L. A Percolative Approach to Investigate Electromigration Failure in Printed Ag Structures. J Appl Phys 2016, 120, 125104–125106.
  20. Lefky, C. S.; Mamidanna, A.; Huang, Y.; Hildreth, O. Impact of Solvent Selection and Temperature on Porosity and Resistance of Printed Self‐Reducing Silver Inks. Phys Status Solidi A 2016, 1–8.
  21. Mamidanna, A.; Song, Z.; Lv, C.; Lefky, C.; Jiang, H.; Hildreth, O. Printing Stretchable Spiral Interconnects Using Reactive Ink Chemistries. ACS Appl. Mater. Interfaces 2016, 8, 12594–12598.
  22. Hildreth, O.; Nassar, A. R.; Chasse, K. R. Dissolvable Metal Supports for 3D Direct Metal Printing. 3D Print. Addit. Manuf. 2016, 3, 91–97.
  23. Liu, S.; Sun, X.; Hildreth, O.; Rykaczewski, K. Design and Characterization of a Single Channel Two-Liquid Capacitor and Its Application to Hyperelastic Strain Sensing. Lab on a Chip 2015, 15, 1376–1384.
  24. Hildreth, O.; Schmidt, D. R. Vapor Phase Metal‐Assisted Chemical Etching of Silicon. Advanced Functional Materials, 2014, 24, 3827–3833.
  25. Hildreth, O.; Honrao, C.; Sundaram, V.; Wong, C. P. Combining Electroless Filling with Metal-Assisted Chemical Etching to Fabricate 3D Metallic Structures with Nanoscale Resolutions. ECS Solid State Letters 2013, 2, 39–41.
  26. Hildreth, O.; Rykaczewski, K.; Fedorov, A. G.; Wong, C. P. A DLVO Model for Catalyst Motion in Metal-Assisted Chemical Etching Based Upon Controlled Out-of-Plane Rotational Etching and Force-Displacement Measurements. Nanoscale 2013, 5, 961–970.
  27. Hildreth, O.; Fedorov, A. G.; Wong, C. P. 3D Spirals with Controlled Chirality Fabricated Using Metal-Assisted Chemical Etching of Silicon. ACS Nano 2012, 6, 10004–10012.
  28. Hildreth, O.; Cola, B.; Graham, S.; Wong, C. P. Conformally Coating Vertically Aligned Carbon Nanotube Arrays Using Thermal Decomposition of Iron Pentacarbonyl. J Vac Sci Technol B, 2012, 30, 03D101–03D101–4.
  29. Hildreth, O.; Rykaczewski, K.; Wong, C. P. Participation of Focused Ion Beam Implanted Gallium Ions in Metal-Assisted Chemical Etching of Silicon. J Vac Sci Technol B 2012, 30, 040603.
  30. Rykaczewski, K.; Hildreth, O.; Wong, C. P.; Fedorov, A. G.; Scott, J. H. J. Guided Three-Dimensional Catalyst Folding During Metal-Assisted Chemical Etching of Silicon. Nano Letters 2011, 11, 2369–2374.
  31. Hildreth, O.; Brown, D.; Wong, C. P. 3D Out-of-Plane Rotational Etching with Pinned Catalysts in Metal-Assisted Chemical Etching of Silicon. Advanced Functional Materials 2011, 21, 3119–3128.
  32. Rykaczewski, K.; Hildreth, O.; Wong, C. P.; Fedorov, A. G.; Scott, J. H. J. Directed 2D-to-3D Pattern Transfer Method for Controlled Fabrication of Topologically Complex 3D Features in Silicon. Mater. 2011, 23, 659–663.
  33. Lin, Z.; Liu, Y.; Yao, Y.; Hildreth, O.; Li, Z.; Moon, K.; Wong, C. P. Superior Capacitance of Functionalized Graphene. The Journal of Physical Chemistry C 2011, 115, 7120–7125.
  34. Rykaczewski, K.; Hildreth, O.; Kulkarni, D.; Henry, M. R.; Kim, S. K.; Wong, C. P.; Tsukruk, V. V.; Fedorov, A. G. Maskless and Resist-Free Rapid Prototyping of Three-Dimensional Structures Through Electron Beam Induced Deposition (EBID) of Carbon in Combination with Metal-Assisted Chemical Etching (MaCE) of Silicon. ACS Appl. Mater. Interfaces 2010, 2, 969–973.
  35. Hildreth, O.; Lin, W.; Wong, C. P. Effect of Catalyst Shape and Etchant Composition on Etching Direction in Metal-Assisted Chemical Etching of Silicon to Fabricate 3D Nanostructures. ACS Nano 2009, 3, 4033–4042.
  36. Lin, W.; Xiu, Y.; Jiang, H.; Zhang, R.; Hildreth, O.; Moon, K.-S.; Wong, C. P. Self-Assembled Monolayer-Assisted Chemical Transfer of in Situ Functionalized Carbon Nanotubes. Am. Chem. Soc. 2008, 130, 9636- 9637.

Patents

Awarded Patents

  1. Hildreth, Y. Xiu, and C. P. Wong. Methods and Systems for Metal-assisted Chemical Etching of Substrates, Patent #US8278191B2, Issued 10/02/2012.
  2. Hildreth. Liquid Deposition Composition and Process for Forming Metal Therefrom, Patent #US9506149 B2, Filed 01/16/2014, Issued 11/29/2016

  3. Hildreth, O. Article with Gradient Property and Processes for Selective Etching, Patent #US9580809 B2, Filed 01/14/2015, Issued 02/28/2017

  4. Hildreth, O. Article and Process for Selective Deposition, Patent #US20150126031, Filed 01/14/2015, Issued 11/07/2017
  5. Hildreth, O. Article and Process for Selective Etching, Patent #US9828677 B2, Filed 03/11/14, Filed 01/14/2015, Issued: 11/28/2017
  6. Hildreth, O.; Jefferies, A.; Mamidanna, A.; and Bertoni, M. Printing using reactive inks and conductive adhesion promoters, Patent #US10286713 B2, Filed 11/11/17, Issued 05/14/2019

Patent Applications Outstanding

  1. Hildreth, O.; Lefky, C.; Abdalla, N.; Simpson, T.; Direct Support Dissolution for 3D Printed Metals and Oxides, Application, #US62/400,464, Filed 09/27/2016
  2. Hildreth, O.; Lefky, C.; Wright, D.; Abdalla, N. Simpson, T.; Dissolving Metal Supports in 3D Printed Metals and Ceramics Using Sensitization, Application #US62/363,034, Filed on 08/17/2016
  3. Hildreth, O.; Abdalla, N.; Simpson, T.; Fabricating Metal or Ceramic Components using 3D printing with Dissolvable Supports of a Different Material, Application #US62/295,912, Filed on 02/16/2016
  4. Hildreth, O.; Hsu, K.; Nassar, A.; Simpson, T.; Process Controlled Dissolvable Supports in 3D Printing of Metal or Ceramic Components; Applications #US62/295,918, Filed on 02/16/2016
  5. Hildreth, O.; Heilig, M.; Raikar, S. Self-Terminating Etching Interfaces Using Iodine-Based Chemistries.  USPO Application #, Filed 03/17/22

Presentations

Short Course Development and Instruction

  1. Hildreth, O*; Li, X.; Short Course on Metal-assisted Chemical Etching for the 2015 Spring meeting of the Materials Research Society

Invited Presentations at Institutes

International Institutes

  1. Hildreth, O*; and Wong, C.P, Fabricating 3D Nano and Micron-sized Structures using Metal-assisted Chemical Etching of Silicon, Deutsches Elektronen-Synchrotron, Hamburg Germany, 2013
  2. Hildreth, O*; and Wong, C.P, Fabricating 3D Nano and Micron-sized Structures using Metal-assisted Chemical Etching of Silicon. École Polytechnique, Paliseau France, 2013

National Institutes

  1. Hildreth, O.*; and Wong, C.P, 3D Nanofabrication Technology using Metal-assisted Chemical Etching of Silicon. Colorado School of Mines, Metallurgical and Materials Engineering Department, Golden, CO, 2013
  2. Hildreth, O.*; and Wong, C.P, Etching 3D Nanostructures in Silicon using Metal-assisted Chemical Etching, Invited talk for Nano@Tech in Atlanta, GA, 2011.
  3. Hildreth, O.*; and Wong, C.P, Cycloids, Spirals, and Sloping Channels: 3D Nanofabrication in Silicon Using Metal-assisted Chemical Etching, Presented at the National Institute of Standards and Technology in Gaithersburg, 2010.

Invited Presentations at Conferences

International Conferences

  1. Hildreth, O*; and Wong, C.P.; Fabricating 3D Nano and Micron-sized Structures using Metal-assisted Chemical Etching of Silicon; Presented at, Metamaterials 2013, Bordeaux France, 2013

National Conferences

  1. Hildreth, O*; Catalyst motion in Metal-assisted Chemical Etching; Presented at Electron, Ion, and Photon Beam Technology and Nanofabrication, Pittsburg, 2016
  2. Hildreth, O*; Simpson, T.; Electrochemistry and corrosion of multi-metal printed structures; Presented at SPIE West, San Francisco, 2016
  3. Wong, CP.; Hildreth, O*.; Recent Advances on Metal-Assisted Chemical Etching (MaCE) for High Performance through Silicon Vias (TSV) Applications. Presented at the Materials Research Society, Spring 2016, Phoenix

Presentations at National Conferences

  1. Lefky, C. S.; Hildreth, O*. High Resolution Electrohydrodynamic Printing of Self-Reducing Silver Ink. Presented at the Solid Freeform Fabrication Conference, Austin 2016
  2. Lefky, C. S.; Nassar, A. R.; Simpson, T. W.; Hildreth, O. Dissolvable Metal Supports for Printed Metal Parts; Presented at the Solid Freeform Fabrication Austin, 2016; pp. 1–10.
  3. Mamidanna, A.; Song, Z.; Lv, C.; Lefky, C. S.; Jiang, H.; Hildreth, O*. Fabrication of a Stretchable Electronics Device Using Reactive Ink Chemistries. Presented at the Solid Freeform Fabrication Conference, Austin 2016
  4. Jefferies, A.; Mamidanna, A.; Hildreth, O.; Bertoni, M. *; Optical Characteristics of Reactive Silver Inks as Front Electrodes for High Efficiency Silicon Heterojunction Solar Cells. Presented at the Materials Research Society, Spring 2016, Phoenix.
  5. Mamidanna, A.; Zhuo, Z.; Alford, T.; Hildreth, O. *; Electromigration Phenomena in Ag and Cu Lines Printed Using Self-Reducing Reactive Inks. Presented at the Materials Research Society, Spring 2016, Phoenix.
  6. Lefky, C.; Hildreth, O*.; High Resolution Electrohydrodynamic Printing of Silver and Glass Reactive Inks. Presented at the Materials Research Society, Spring 2016, Phoenix.
  7. Arnold, G.#; Lefky, C.; O*.; Non-Contact Location System for Precision Placement Of Nanostructures in EHD Printing. Presented at the Materials Research Society, Spring 2016, Phoenix.
  8. Huang, Y.; Mamidanna, A; Hildreth, O*.; Drop-on-Demand Printing of SiO2 Dielectrics from Sol-gel Chemistries. Presented at the Materials Research Society, Spring 2016, Phoenix.
  9. Mamidanna, A.; Lv, C.; Song. Z.; Jiang, H.; Hildreth, O*.; Inkjet Printed Serpentine Stretchable Electronics Using Reactive Ink Chemistries. Presented at the Materials Research Society, Spring 2016, Phoenix.
  10. Jeffries, A.; Mamidanna, A.; Clenney, J.; Ding, L.; Hildreth, O.; Bertoni, M*. Innovative Methods for Low-Temperature Contact Formation for Photovoltaics Applications. Presented at the IEEE Photovoltaics Specialists Conferece; New Orleans, 2015; pp. 1–5.
  11. Hildreth, O*.; Catalyst motion in Metal-assisted Chemical Etching, Presented at the Materials Research Society, Spring 2015, Phoenix.
  12. Mamidanna, A.; Lefky, C.; Hildreth, O*. Ink Composition of PEG Filler Inks for Printed 3D Microfluidic Devices. Presented at the Materials Research Society, Spring 2015, Phoenix.
  13. Hildreth, O and C. P. Wong, Fabricating chiral 3D, micron- to nano-sized structures in a single lithography/etch cycle using Metal-assisted Chemical Etching. Presented at the Materials Research Society Spring Meeting in San Francisco, CA, 2013
  14. Hildreth, O and C. P. Wong, Out-of-Plane Rotation in Metal-Assisted Chemical Etching for Complex 3D Nano-scale to Micron-scale Manufacturing, Presented at the Materials Research Society in San Francisco, CA, 2011.
  15. Hildreth, O and C. P. Wong, Motility of silver nanorods in metal-assisted chemical etching of silicon, Presented at the Proceedings of the Materials Research Society in San Francisco, CA, 2010.
  16. Hildreth, O, C. Alvarez, and C. P. Wong, Tungsten as a CMOS compatible catalyst for the metal-assisted chemical etching of silicon to create 2D and 3D nanostructures, Presented at the Electronic Components and Technology Conference in Las Vegas, NV, 2010.
  17. Hildreth, O, W. Lin, C. Alvarez and P. Wong .Novel Method to Extract Arrays of Aligned Carbon Nanotube Bundles from CNT film using Solder Ball Grid Arrays for Higher Performance Device Interconnects. Paper presented at the Electronic Components and Technology Conference, San Diego 2009.
  18. Hildreth, O, Y. Xiu and C. P. Wong. Wet Chemical Method to Etch Sophisticated Nanostructures into Silicon Wafers using sub-25nm Feature Sizes and High Aspect Ratios. Paper presented at the Electronic Components and Technology Conference, 2009.
  19. Li, Y.; Zhang, R.; Zhu, L.; Lin, W.; Hildreth, O.; Jiang, H.; Lu, J.; Xiu, Y.; Liu, Y.; Moon, J.;. NANO Materials and Composites for Electronic and Photo Packaging. In Presented at 9th IEEE Conference on Nanotechnology; 2009, 1–3.

Awards

PI/Hildreth Awards

  • 2022 President’s Award for Excellence in Safety (Colorado School of Mines)
  • 2020 National Science Foundation CAREER Award
  • 2017 TechConnect Defense Innovation Award
  • 2015 Bisgrove Scholar Early Career Award
  • 2012 National Research Council Postdoctoral Fellow
  • 2011 MSE Graduate TA Award, Georgia Institute of Technology
  • 2010 MSE Graduate TA Award, Georgia Institute of Technology

Student Awards

  • 2022   Steven DiGregorio – Mechanical Engineering Graduate Presentation Competition Winner
  • 2021   Stephanie Prochaska – ICAM Student Presentation Competition Winner
  • 2020   Steven DiGregorio – Mechanical Engineering Graduate Presentation Competition Winner