Discipline: Technology and Engineering
Subcategory: Materials Science
John Patrick Harris - Norfolk State University
Thermoelectricity is an area of “green” research that can be used to help reduce the dependence on fossil fuels by using waste heat to generate energy. Molybdenum Disulfide (MoS2) a thermoelectric semiconducting material has desirable thermoelectric properties at high temperature to collect heat and convert to electricity. The regained electricity can be used in the form of a thermoelectric generator as power. The application of this type of material can be used in applications such as optoelectronics, and solar cells for energy harvesting. High quality conformal growth of several samples of Molybdenum Disulfide of different thicknesses will be achieved using pulse-laser deposition on p-type Silicon substrates to make p-n junctions. The characteristics of MoS2 was characterized by current-voltage, temperature dependent resistivity using four point probe, Atomic Force Microscope (AFM), Seebeck Coefficient and Raman. The results obtained show that Molybdenum Disulfide shows very favorable currentvoltage characteristics, and when tested for photovoltaic characteristics using the same instrument it also displays good optoelectronic properties under different applications of light of different power. The measurement of the resistivity of one material of Molybdenum Disulfide was obtained using the fourpoint probe and analyzed against as temperature was increased. The sample of MoS2 that was grown at 4000 pulses shows that as the temperature of the material is increased the resistance of the material decreases. The AFM of four samples of MoS2 grown at 500, 1000, 2000, and 4000 pulses with the PLD shows a smooth surface characteristic which allows good transportation of electrons through the surface. The Seebeck of MoS2 shows that it operates at a high value over a wide range of temperature and has a peak value around 470 K which is optimal for seizing waste-heat energy in automobiles. The results obtained from the Raman Spectroscopy were also obtained and displayed here in the report. Further analysis of MoS2 will need to be done to help understand the results obtain for this report. However the material of MoS2 shows favorable characteristics that indicate that it is material that can be used in a thermoelectric capacity and serve a dual role as a solar collector as well. This type of material will have to be characterized to find its thermal conductivity and after doing that the figure of merit (ZT) can be determined to understand how efficient a material like MoS2 can be.
Funder Acknowledgement(s): CREST
Faculty Advisor: Aswini Pradhan / Sangram Pradhan,