Structural and Electrical Characterization of (BiₓSb₁₋ₓ)₂Te₃
Board Location: #137
Discipline: Nanoscience or Materials Science
Session: 3
Adrian Rua - University of Puerto Rico - Mayaguez
Co-Author(s): Candice Forrester, Sina Mohammadi, Kaushini Wickramasinghe, María Tamargo Department of Chemistry, Lehman College, CUNY, Bronx, NY 10468 Department of Physics, The City College of New York, CUNY, New York, NY 10031 Department of Chemistry, The City College of New York, CUNY, New York, NY 10031 Doctoral Program in Chemistry, Graduate Center of CUNY, New York, NY 10016
In this work we characterized topological insulator films of (BiₓSb₁₋ₓ)₂Te₃ of different compositions that were grown by molecular beam epitaxy (MBE) by varying the growth conditions. Several samples were grown having different values of x. We would like to determine the value of x that yields the lowest bulk carrier density. A low bulk carrier density would allow us to observe the topological surface states. We used high resolution X-ray diffraction to measure the composition of the samples grown. While the out-of-plane lattice constant remains unchanged with composition, we showed that the in-plane lattice constant depends on the composition, allowing us to determine the value of x for each sample. Comparison of the composition of the layers with the flux ratios used during MBE growth showed that the composition could be predicted for most of the samples by adjusting the flux ratio used during growth. Deviations form this correlation suggests that sometimes other factors also affect the composition. Hall Effect measurements will be pursued in order to verify the relationship between carrier density and composition of the materials.
Funder Acknowledgement(s): This research was supported in part by NSF REU programs: IDEALS (HRD2112550) and IDMNYC DMR-1950573 (IDMinNYC)
Faculty Advisor: Dr. Maria Tamargo, mtamargo@ccny.cuny.edu
Role: My role was as a research assistant during the summer, where I worked on the characterization of the (BiₓSb₁₋ₓ)₂Te₃ material. Specifically, we conducted detailed analysis to assess its structural, electrical, and thermal properties. This involved using various techniques, such as X-ray diffraction (XRD) for phase identification and resistivity measurements like Hall Effect to study the material's conductivity. Additionally, I assisted in data collection and interpretation to understand how composition variations influenced the material's performance, contributing to our overall understanding of its potential applications in thermoelectric devices.