2D materials based heterostructures : a lithography free method.

Abstract

supportive and kind to me throughout this journey. I got to learn a lot from his experience, his feedback has always been of great asset and I am honored that I got the opportunity to be under his worthy guidance and to be in his prestigious research team. The knowledge and skills that I learned from him, have played a huge role in the enhancement of my scientific career. Next, I want to thank all the teachers who have taught me courses during my Ph.D. course-work, particularly, Dr. Chakram S. Jayanthi, the Chair-person of Physics Department at the University of Louisville, and, Dr. Ming Yu, Professor in Physics who taught me some valuable courses. It was a delight to be their student and I feel honored to call myself their student. I would further like to thank Dr. Chris. L Davis who is my graduate program advisor, whose advice has been very fruitful for me right from choosing courses to important decision during my Ph.D. journey. Dr. Chris. L Davis is not only a great student advisor but also a great gentleman who is always nice, kind and polite to his students. I will always remain grateful for the kindness that he showed towards me. x 2.5.2 Scanning Electron Microscope .

Direct fabrication and characterization of vertically stacked Graphene/h-BN/Graphene tunnel junctions

“…Figure 3 shows the x-ray photo-emission spectroscopy (XPS) results of h-BN grown by PECVD. The survey spectrum shown in figure 3(a) clearly shows the presence of boron and nitrogen with the appearance of XPS peaks corresponding to B1s and N1s core electrons [34]. As expected, an additional peak corresponding to O1s core electrons is also present in the survey spectrum.…”

“…The samples were then cooled down to room temperature at a rate 25 °C min −1 . Finally, the third graphene layer was deposited as before using another mask with a smaller opening [34].…”

“…The PECVD technique allows the growth of graphene on both conductive and insulated substrates with almost the same quality. The Raman spectrum of h-BN consisting of a peak at ∼1367 cm −1 with the FWHM of 13 cm −1 which is assigned to the high-frequency vibrational mode (E 2g ) [34].…”

“…Heterostructures play a vital role in semiconductor industry. The newly developed monolayer 2D materials offer a platform that allows creation of heterostructures with a variety of novel properties [34].Many structural, physical, and chemical properties have been explored on Van der Waals heterostructures created by monolayers of multiple 2D materials with vertically stacked layered heterojunctions [35][36][37][38][39]. Since these heterostructures utilize the Van der Walls interlayer interaction, lattice matching is no longer a significant factor.…”

“…Such graphene-TMDs structures have been introduced for various device applications and, also been of particular interest in the spectroscopy community [38,[42][43][44]. For example, many groups demonstrated the vertical tunneling transistors with high on-off ratios and large current densities that used TMDs thin layers as tunneling barriers and graphene as one or both electrodes [34,35,38,40,45].…”