Dr. John Colton, Department of Physics and Astronomy

How well the academic objectives of the proposed research were met, along with a description of the results and findings of the project

The proposed project was to study three specific semiconductor nanostructure materials systems: defects in silicon carbide (SiC), ferritin-based nanoparticles, and germanium (Ge) quantum dots. The first two projects happened; however, the Ge project, which was to be a partnership between myself and a professor at Boise State, did not happen because our NSF grant proposal on the topic was not funded. So, I will focus on the first two areas:

– Defects in SiC – We used optical techniques to study the spin properties (in particular the spin coherence lifetimes) of electronic states in the silicon vacancy defect in SiC; between us and our collaborators at the Naval Research Lab, four different samples were investigated, having different defect densities. Our experiments were done for two of the samples as a function of temperature (from 8 to 295 K), using microwaves to stimulate electron spin resonance at a microwave frequency of 10.49 GHz and a magnetic field of 0.371 T. We found that the spin coherence times ranged out to 270 μs, but displayed unusual temperature dependences that we attributed to a “motional Jahn-Teller effect”. We also found that a significant source of the spin dephasing was from dipole-dipole interactions between Si vacancies or with other defects produced by the proton irradiation, and that there was likely an inhomogeneous distribution of defect spins. Three BYU students along with one visiting student were involved in this research during the grant period. This led to a peer-reviewed journal publication that I will list below.
– Ferritin-based nanoparticles (NPs)– We have worked on several projects related to nanoparticles (NPs; bits of semiconductor <8 nm in diameter) inside the hollow protein, ferritin. Some of these are still ongoing. Ten BYU undergrads have been involved in this research, along with one visiting student and one visiting high school teacher.

•  Using ferritin-NPs to absorb light in solar cells. This led to a peer-reviewed journal publication that I will list below.
•  Creating new synthesis techniques to form MnO and CoMnO NPs in the core of ferritin, and studying their properties (esp. optical absorption). This led to two peer-reviewed publications that I will list below.
•  New synthesis techniques to make PbS, PbSe, and PbTe NPs inside ferritin. This has led to a paper being submitted (not accepted yet), and another paper in draft form.
•  Ongoing research in using ferritin-NPs to create platinum nanoparticles for use as an photocatalyst. We hope this will lead to a paper.
•  Ongoing research to study the conductivity of different types of ferritin-based NPs. We hope this will lead to a paper.

In addition to the four peer-reviewed articles mentioned above, the paper which has been written but not yet accepted, the research also led to three senior theses (see below for a list), and 23 student research presentations at local, regional, and national conferences. The student presentations include several which won “Best in Session”-type awards. This funded research will also undoubtedly contribute to several additional papers, senior theses, and talks. Based on that, I would say that the academic objectives were met extremely successfully.

Evaluation of the mentoring environment

I believe the mentoring experience was extremely successful! The students learned what “real research” involves, and they made meaningful contributions to it. I have written numerous letters of 2 recommendation for the students who participated in this MEG grant as listed below. The students who have graduated are all employed or in graduate school. Graduate schools include UT Austin, Georgia Tech, Duke, and Columbia.

List of students who participated and academic deliverables (including anticipated)

The following individuals participated in this research during the grant period (only dates from Jan 2016 – Dec 2017 are shown):

Undergraduate students:

• Daniel Boyce (Sep 2017 – Dec 2017)
• Charles Lewis (Sep 2017 – Dec 2017)
• James Erickson (Sep 2017 – Dec 2017)
• Matt Richards (Aug 2017 – Dec 2017)
• Micah Shelley (Sep 2016 – Dec 2017)
• Heather Hogg (Sep 2016 – Dec 2017)
• Scott Crossen (Jan 2016 – Dec 2017)
• Ryan Peterson (Jan 2016 – Dec 2017)
• Alessandro Perego (Jan 2016 – Dec 2017)
• Kameron Hansen (Jan 2016 – Apr 2017)
• Luis Perez, visiting student (summer 2016)
• Cameron Olson (Jan 2016 – Apr 2016)
• Michael Meehan (Jan 2016 – Apr 2016)
• Jacob Embley (Jan 2016 – Apr 2016)

Visiting high school teacher:

• Barbara Austin, visiting teacher (summer 2017)

The following academic deliverables were achieved during the grant period: (student co-authors marked with an asterisk)

Publications

1. “Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics,” K.R. Hansen, J.R. Peterson, A. Perego, M. Shelley, C.R. Olsen, L.D. Perez, H.L. Hogg, R.K. Watt, and J.S. Colton, submitted but not yet accepted.

2. “Tuning ferritin’s band gap through mixed metal oxide nanoparticle formation,” C.R. Olsen*, J.S. Embley*, K.R. Hansen*, A.M. Henrichsen*, J.R. Peterson*, J.S. Colton, and R.K. Watt, Nanotechnology 28, 195604 (2017). Available at https://doi.org/10.1088/1361-6528/aa68b0.

3. “Permanganate-based synthesis of manganese oxide nanoparticles in ferritin,” C.R. Olsen*, T.J. Smith, J.S. Embley*, J.H. Maxfield*, K.R.Hansen*, J.R. Peterson*, A.M. Henrichsen*, S.D. Erickson*, D.C. Buck, J.S. Colton, and R.K. Watt, Nanotechnology 28, 195601 (2017). Available at https://doi.org/10.1088/1361-6528/aa68ae.

4. “Fabrication of dye sensitized solar cells using native and non-native nanocrystals in ferritin as the dye,” A. Perego*, C. Olsen*, J.R. Peterson*, K. Hansen*, J.S. Colton, and R.K Watt, J. Utah Academy of Sciences, Arts, & Letters 2016, 183 (2017). [This paper won the “Outstanding Paper Award” in the Engineering category, and a figure from this paper was selected as the cover image of the journal.] Available at http://www.utahacademy.org/wp-content/uploads/2015/01/JUASAL-2016-full-text-finalrevised. pdf.

5. “Electron spin coherence of silicon vacancies in proton-irradiated 4H-SiC,” J.S. Embley*, J.S. Colton, K.G. Miller*, M. A. Morris*, M. Meehan*, S.L. Crossen*, B.D. Weaver, E.R. Glaser, and S.G. Carter, Phys Rev B 95, 045206 (2017). Available at https://doi.org/10.1103/PhysRevB.95.045206.

Senior theses which included work from the grant period:
1. Kameron Hansen – “Ferritin encapsulated PbS, PbSe, and MoS2 Nanocrystals for Photovoltaic Applications”, Apr 2017
2. Cameron Olsen – “Permanganate-Based Synthesis of Semiconducting Metal Oxide Nanoparticles in the Protein Ferritin”, Apr 2016
3. Jacob Embley – “Electron Spin Coherence in Silicon Vacancy Defects of Proton-irradiated Silicon Carbide”, Apr 2016

Conference talks given by students which included work from the grant period: (student co-authors marked with an asterisk)
1. “ODMR: Computation and Experiment,” S.L. Crossen*, J.S. Colton, Meeting of the Four Corners Section of the American Physical Society, Fort Collins, CO, Oct 21, 2017.

2. “Tunability and Stability of Lead Sulfide Quantum Dots in Ferritin,” J.R. Peterson*, J.S. Colton, K. Hansen*, M. Shelley*, A. Perego*, C. Olsen*, and L. Perez *, Abstract L27.04, American Physical Society March Meeting, New Orleans, LA, Mar 15, 2017.

3. “Nanocrystals Inside Ferritin Inside Photovoltaic Cells,” K. Hansen*, J. Colton, R. Watt, J.R. Peterson*, C. Olsen*, A. Perego*, L. Perez*, and H. Longstaff*, Abstract L25.03, American Physical Society March Meeting, New Orleans, LA, Mar 15, 2017.

4. “Efficiency of Dye-Sensitized Solar Cells Using Ferritin-Encapsulated Quantum Dots With Various Staining Methods,” L. Perez*, J.S. Colton, K. Hansen*, J.R. Peterson*, Abstract C12.03, American Physical Society March Meeting, New Orleans, LA, Mar 13, 2017.

5. “Electron Spin Coherence in Silicon Carbide,” S. L. Crossen*, J. Colton, Brigham Young University Student Research Conference, Provo UT, Mar 4, 2017.

6. “Fabrication of Dye-Sensitized Solar Cells Using Nanocrystals in Ferritin as the Dye” A. Perego*, K. Hansen*, J. R. Peterson*, J. Colton, R. Watt, Brigham Young University Student Research Conference, Provo UT, Mar 4, 2017.

7. “Tunability and Stability of Lead Sulfide Quantum Dots,” J.R. Peterson*, J.S. Colton, K. Hansen*, M. Shelley*, A. Perego*, C. Olsen*, L. Perez*, Brigham Young University Student Research Conference, Provo UT, Mar 4, 2017.

8. “Synthesis of Platinum Nanoparticle Coated Ferritin for Photocatalytic Water Splitting,” A. Henrichsen*, D. Petrucci, J. Colton, R. Watt, C. Olsen*, Brigham Young University Student Research Conference, Provo UT, Mar 4, 2017.

9. “Characterizing PbS, PbSe, and MoS2 Quantum Dots in Ferritin,” H. Longstaff*, J. Colton, R. Watt, K. Hansen*, J.R. Peterson*, M. Shelley*, Brigham Young University Student Research Conference, Provo UT, Mar 4, 2017.

10. “Electron Spin Coherence in Silicon Carbide,” S.L. Crossen*, J. Colton, J. Embley*, Joint Meeting of the Four Corners and Texas Sections of the American Physical Society, Las Cruces, NM, Oct 22, 2016.

11. “Using Ferritin Quantum Dots to Harvest Solar Energy,” K. Hansen*, J. Colton, R. Watt, P. Minson, J.R. Peterson*, A. Perego*, C. Olsen*, Joint Meeting of the Four Corners and Texas Sections of the American Physical Society, Las Cruces, NM, Oct 22, 2016.

12. “Lead Sulfide Quantum Dot Band Gap Investigations,” J.R. Peterson*, J.S. Colton, K. Hansen*, L. Perez*, C. Olsen*, Joint Meeting of the Four Corners and Texas Sections of the American Physical Society, Las Cruces, NM, Oct 21, 2016. 4

13. (invited) “Quantum dots inside ferritin to harvest solar energy,” K. Hansen*, J. Colton, R. Watt, P. Minson*, J.R. Peterson*, A. Perego*, Brigham Young University Physics Department colloquium, Provo UT, Sep 7, 2016.

14. “Harvesting Solar Energy Using Bioinorganic Nanoparticles,” C. Olsen*, J. Embley*, A. Perego*, J. Colton, and R. Watt, Utah Energy Summit, Governor’s Energy Development Summit, Salt Lake City UT, May 25, 2016.
o This poster was selected to be part of the Harold B. Lee Library’s exhibit on mentored research, and was on display in the library from Aug 2016 – approx. Oct 2016.

15. “Fabrication of Dye Sensitized Solar Cells Using Native and Non-Native Nanocrystals in Ferritin as the Dye,” A. Perego*, J. Colton, and R. Watt, AIChE Rocky Mountain Regional Conference, Tucson AZ, Apr 2, 2016.
o This talk won 2nd place in the paper competition.

16. “Synthesis of Platinum Nanoparticle Coated Ferritin for Photocatalytic Water Splitting,” A. Henrichsen*, J. Colton, R. Watt, and C. Olsen *, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016.

17. “Electron Spin Coherence in Silicon Carbide,” S. Crossen*, J. Colton, and J. Embley*, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016.

18. “Semiconductor Band Gap Measurements,” J.R. Peterson* and J. Colton, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016.

19. “Lead Sulfide (PbS) Quantum Dots inside Ferritin,” K. Hansen*, J. Colton, R. Watt, and C. Olsen*, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016.

20. “Fabrication of Dye Sensitized Solar Cells Using Native and Non-Native Nanocrystals in Ferritin as the Dye,” A. Perego*, J. Colton, and R. Watt, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016.

21. “Measurement of Spin Coherence Times in Proton-Irradiated 4H-SiC,” J. Embley*, J. Colton, S. Carter, M. Morris*, K. Miller*, and M. Meehan*, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016. o This talk won a “Best in session” award.

22. “Bio-Inorganic Nanoparticles for Improved Solar Energy Harvesting,” C. Olsen*, J. Embley*, K. Hansen*, J.R. Peterson*, A. Henrichsen*, A. Perego*, J. Colton, and R. Watt, Brigham Young University Student Research Conference, Provo UT, Mar 19, 2016.
o This talk won a “Best in session” award.

23. “Measurement of Spin Coherence Times in Proton-Irradiated 4H-SiC,” J. Embley*, J. Colton, S. Carter, M. Morris*, K. Miller*, and M. Meehan*, Abstract Y5.14, American Physical Society March Meeting, Baltimore MD, Mar 18, 2016.

Description of how the budget was spent

The budget was originally allocated as follows:

Undergrad research $18000
Supplies $2000

However, since the College of Physical and Mathematical Sciences greatly expanded their support of undergraduate student research, I did not end up using quite that much. Here are the details on the spent funds:

Undergrad research in 2016 $7711
Supplies in 2016 $1059
Undergrad research in 2017 $2175
Supplies in 2017 $6094 5

Total $17039

The funds in the undergrad research category were used to support these students as research assistants either partially or fully during the grant period:

• Scott Crossen
• Jacob Embley
• Kameron Hansen
• Drew Henrichsen
• Alessandro Perego
• Ryan Peterson
• Micah Shelley

The funds in the Supplies category were used to pay for optics, chemicals, chemical filters, other items from Chem Stores, TEM time (microscope), group meeting refreshments, and things of that nature.

Note that these charges do not include December 2017; the “Supplies in 2017” amount will certainly increase a bit after December.

Since I was given $20000 for the grant and only have spent $17039 (not including Dec), $2961 of the grant funds remain. I have not applied for a MEG grant for the coming year, and assuming I don’t have to return the left-over money, I plan to continue to spend the $2961 on similar student research expenses until it is used up.