Events Calendar

Physics Colloquium - Graduate Student Presentations

This is a past event.

Thursday, March 17, 2022, 4 pm– 5 pm

This is a past event.

Thursday, March 17th at 4pm – Fisher Hall 139 & Zoom

Hybrid-Mode: The students will give their talks in Fisher Hall 139. Please join in-person or by zoom.


Sambhawana Sharma

[Advisors: Dr. Dongyan Zhang and Dr. Yoke Khin Yap]

Exploring the use of boron nitride dots for biomedicine

Fluorescence microscopy is essential for imaging biological cells' intercellular and intracellular activities. Organic dyes are widely used as fluorescent tags to label proteins, deoxyribonucleic acids (DNAs), and ribonucleic acids (RNAs). Unfortunately, the fluorescence brightness of organic dye is low and not stable as irradiated by laser. We can resolve these issues by using high-brightness fluorophores (HBFs) developed by MTU1. HBF increases the fluorescence brightness by 10x to 1000x by preventing fluorescence quenching on boron nitride nanotubes (BNNTs). Here we will explore the biocompatibility of boron nitride (BN) dots as a new class of fluorescence materials for biomedical application.

First, we have studied the biocompatibility of BN dots on HeLa cells (human cancer cells). Trypan blue and DNA assays indicate that BN dots are biocompatible. We are currently exploring BN dots as the fluorescent label of RNAs by using the single-molecule Fluorescence in-situ Hybridization (sm FISH) technique. 

1(Review) D. Zhang, S. Zhang, N. Yapici, R. Oakley, S. Sharma, V. Parashar, and Y. K. Yap, “Emerging Applications of Boron Nitride Nanotubes in Energy Harvesting, Electronics, and Biomedicine.” ACS Omega 620722–20728 (2021).



Manpreet Boora   [Advisor: Jae Suh]

Precise Control of Interlayer Twist Angle using Etchant-free Thin Film Transfer Method

Two-dimensional transition metal dichalcogenides (TMDs) have attracted great attention because of their scalability and tunability of optical bandgaps depending on the number of stacked layers. Twisted TMDs are even more interesting because of the additional degree of freedom from twist angle, which provides a controllable playground for studying phonon-phonon couplings, twist angle-dependent interlayer excitons, and charge transfer dynamics. A monolayer of TMDs has a stoichiometry of MX!Where M is a transition metal (M = W or Mo) sandwiched between two layers of chalcogen atoms (X = S, Se or Te). For twisted bilayer graphene, the magic angle is 1.1°, and the flat band appears only for a narrow range of twist angles (1.1° ± 0.1°). For TMDs, however, there exists a wider range of twist angles, spanning from 4° to 5°. Moreover, long-wavelength Moiré superlattices arise either from a difference in the lattice constant or a twist angle between two stacked layers. These Moiré patterns in twisted TMD bilayers have emerged as a highly tunable platform for studying strongly correlated electron physics. Our research focuses on the precise control of interlayer twist angle with a clean and large interfacing area. We will discuss Raman spectroscopy results, showing the evolution of interlayer coupling in twisted TMDs.



Rishi Babu  [Advisor: Petra Huentemeyer]

HAWC Study of J1809-190 - A Source Rich Region

The region surrounding 3HWC J1809-190 is a TeV source rich region comprised of multiple source classes such as pulsars and supernovas. The very high energy gamma ray source was first observed by the High Energy Stereoscopic System (H.E.S.S.) and the exact source association is not clear and the possibility of a pulsar wind nebulae association. Studies have suggested that the gamma rays follow a hadronic scenario for the source. Morphological studies have indicated an extended source in this region with the source being detected above 100TeV. Studies with High Altitude Water Cherenkov (HAWC) detector are being performed to check the spectral energy distribution(SED) to confirm the hadronic origin of the gamma rays and the existence of a galactic PeVatron in the region that accelerates particles up to Peta electron-volt(PeV) energies.

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