Discipline: Technology and Engineering
Subcategory: Materials Science
Shanece Esdaille - University of the Virgin Islands
Two-Dimensional materials are a class of nanomaterials that are approximately one or two atoms thick. Graphene is most commonly associated with 2-D materials. It is our first contact in next generation electronic devices based on hetero-stacks of 2-D material. In particular, exploring contact doping as an interface to modify the work function of the interface. In addition to Graphene, Molybdenum disulfide was also looked at as another 2-D material to replace silicon in electronic devices. These 2-D materials were doped with other materials or impurities to determine the chemical properties of their structure. X-ray photo election spectroscopy (XPS) was used to analyze these samples and Igor procedures was used as the software to analyze the data. X-ray photoelectron spectroscopy is a surface-sensitive quantitative spectroscopic technique that measures the elemental composition at the parts per thousand range, empirical formula, chemical state and electronic state of the elements that exist within a material. The project involved the tuning of electronic structures of 2-Dimnesional sheets of Nano-materials by the exploration of chemical doping of both graphene as an electrode and a single layer transition metal dichalcogenide (TMDC) such as MoS2. In particular, focus was placed on chlorine doped graphene and chlorine doped MoS2 in the monolayer limit and in Van der Waal’s hetero-stacks with an eye on next generation post silicon electronic devices. The calculated atomic concentrations and work function shifts agrees with theory in relation to chemical compositions and bond type. For chemical doping which is our chlorinated samples, it was observed that there is strong p-type bonding of almost 1ev; whereas in contact doping such as in Chlorinated Graphene layered on top of MoS2, these are strongly n-type bonding. From this we deduce that n-type doping occurred because the samples required a lot of charge and this suggests that contact doping really changes the game as it relates to the new age of electronics. As a result, we are now able to connect atomistic bond environment with electronic structure effects in 2-D materials.
Funder Acknowledgement(s): Materials Research Science and Engineering Center (MRSEC); BioIGERT; Optics IGERT; Center for Integrated Access Networks (CIAN); NSF grant # 1420634.
Faculty Advisor: Wayne Archibald, firstname.lastname@example.org
Role: I conducted the data analysis which includes the interpolation of spectra/waves from the surface analysis techniques. I also did all the calculations such as linear background subtractions, atomic concentrations, work function shifts and other calculations relating to these. All the graphs and illustrations I created based on these results and findings. From all of this I based and wrote the conclusion, research findings and future work.