Subcategory: STEM Research
Rami Bommareddi - Alabama A&M University
Co-Author(s): B. Rami Reddy, Vernessa M. Edwards, Satilmis Budak, Michael Curley, Matthew Edwards, Ashok Batra, Padmaja Guggilla, Kristopher Liggins, Marcus Pugh, Samuel Uba and Bir Bohara
The research project has three subtopics on (1) nanostructured glasses for energy efficient light sources, (2) thermoelectric semiconductor nanolayer devices and (3) nanocomposite thin films for energy harvesting, and several educational outreach activities. (1) A Sodium borate glass was made by the melt quenching technique. The glass was embedded with Tb3+, Sm3+ and Dy3+. The sample was characterized by spectroscopic methods. When the sample was excited with 405 nm and 375 nm diodes, it revealed warm white light. Color coordinates and temperatures have been measured. Preliminary results have been communicated to a conference. Further work is in progress. (2) A few multilayer thin film devices were made from Ni/Bi2Te3/Sb2Te3/Ni, Ge/Bi2Te3/Sb2Te3/Ge, Bi2Te3/Sb2Te3, Ni/Bi2Te3/Ni, Ni/Sb2Te3/Ni, SiO2/Au. Later on, these samples were annealed to form quantum structures in the fabricated thin film systems to improve the thermoelectric properties. Seebeck coefficient and van der Pauw resistivity measurements have been performed. Preliminary results have been communicated to a conference. Further work is in progress. (3) Effect of external magnetic field on the performance of piezoelectric cantilever/energy harvester has been considered. A comparison of the experimental data of different configurations showed a good enhancement of the energy harvester when an external magnetic field was added to the piezoelectric cantilever beam (PCB). The performance of the energy harvester was further enhanced when magnetic, thermal, and mechanical effects were included. We have implemented variational theory and partial differential equations (PDEs) techniques as a means of using density functional theory to obtain minimized electronic states of conduction electrons, to understand the energy harvesting materials and make further improvements. These calculations can enhance our understanding of such states in amorphous and crystalline thin films. Preliminary calculations have yielded soliton type solutions in PDE methods. Further work is in progress. Educational outreach: Six school students and a teacher participated for a month, from June 12 to July 12 in the research activities of the project. Students spent the first week in nanocomposite film labs; second week in semiconductor thin film lab, third week in the summer workshop on Nanotechnology and the fourth week in spectroscopy lab. A four day workshop was conducted on Nanoscience and Technology. The average attendance was about 35. This includes faculty, students and out of state students. Twelve students and two faculty members were invited from outside. Five experts were invited to deliver lectures on different topics of Nanoscience and technology.
Funder Acknowledgement(s): NSF HBCU RISE Grant HRD 1546965.
Faculty Advisor: None Listed,