(7jo) Functional 2D Material Heterostructures and Bio-Interfacing for Sustainable Energy Generation

The quantum confinement of charge carriers in two-dimensional nanomaterials (2DNs) evolve new and in several cases superior electronic and optical properties with applicability in solar energy conversion, quantum transport-based nanoelectronics, and bio-nano interfacing. The challenge is how to control the nucleation of these 2DNs and their quantum heterostructures for engineered properties. Owing to the Van Hove singularity in the electronic density of states, the 2D semiconductors exhibit strong light-matter interactions and can be coupled with bulk semiconductors or biological entities to create sustainable energy generations. For the past 8 years of my doctoral and post-doctoral training and research assistant professorship positions, I have built a solid foundation by addressing these challenging questions.

My graduate research was a result of research exposure from three countries with two scholarships including Commonwealth scholarship for doctoral exchange research at The University of Saskatchewan, Canada and second one is a Department of Science and Technology sponsored travel grant for visiting Technical University of Denmark for Ph.D. summer school on challenges in 2D materials. In the group of Prof. Qiaoqin Yang at The University of Saskatchewan, Canada, I primarily focused on developing strategies for synthesis of vertical graphene films with enhanced electron field emission characteristics. I have developed a novel strategy to produce high aspect ratio silicon nanowires directly on SiO2/Si surfaces via oxidation and reduction in hydrogen environment. These nanowires exhibited quantum confinement effect as confirmed by Raman spectroscopic analysis.

My postdoctoral research with Prof. Vikas Berry at The University of Illinois at Chicago (UIC) involved nanoscale designing and bottom-up synthesis of 2D material heterostructures for low-temperature quantum transport and optoelectronics. Currently the quantum heterostructures are assembled by transferring the 2D materials produced on transition metal catalytic surfaces. These polymer-assisted transfer approaches introduce scattering centers for charge carrier transport and recombination centers for photovoltaic solar cells. To address this challenge, I have developed novel surface-chemical-interaction chemistry to nucleate graphene, h-BN and their heterostructures directly on oxide and nitride-based gate-dielectric substrates and investigated low-temperature quantum transport phenomena. I have developed mechanistic understanding of epitaxial graphene formation with ultra-high Raman I2D/IG ratio on Co (1 1 1) surfaces. I have also designed experiments to comprehend the photovoltaic and quantum efficiency characteristics in advanced 2D layer-interfaced-3D bulk semiconductor photojunctions for efficient photovoltaic sensors.

In my current role as Research Assistant Professor at UIC, I have focused on understanding the structure-property correlations of 2-atom, 3-atom, 4-atom thick 2D materials and interfacial photophysics of 2D-on-3D material junctions. With collaboration with Dr. Anirudha Sumant (Argonne National Laboratory) and Prof. Gajendra Shekhawat (Northwestern University), I am currently investigating two important experimental phenomena on piezoelectricity in 2D semiconductors and role of nanocrystalline diamond as an electron blocking inter-layer in graphene photovoltaic sensors. In the last 11-month period, I as a Co-PI received a grant of US$ 1,500 for a project on ‘printing graphene-based solar cells’ under UIC-Women in Engineering Summer Program 2017 and as a PI submitted several proposals including: (i) Samsung Global Research Outreach Program (US$ 100,062) and (ii) Centre for Nanoscale Materials, Argonne National Laboratory (User Research Proposal). I have also organized two graduate research and career symposiums in UIC Department of Chemical Engineering during fall of 2016 and 2017 and reviewed about 40 papers.

Research Interests:

With a solid foundation in the physics of two-dimensional (2D) materials for opto-plasmonic-based heterojunction-photovoltaics, low-temperature quantum transport, molecular-surface-functionalization, and bio-nano interfacing, research projects with high possible throughput are being targeted. My goal is to establish an independent research program that aims in developing four major projects: (A) New 2D Materials and Quantum Heterostructures Development: mechanistic understanding of growth chemistry for 1-atom, 2-atom, 3-atom, 4-atom, 5-atom thick inorganic 2D materials and complex heterostructure circuits and their fundamental structure-property correlations, (B) Energy Harvesting and Quantum Electronics: 2D materials-based emerging plasmonic-heterojunction-photovoltaics and low-temperature quantum transport in nano(opto)electronic circuits, (C) Materials Chemistry: non-covalent and vapor-phase surface functionalization and doping/bandgap engineering of the 2D materials to control the electronic structure towards efficient device functionality; and (D) Bio-Nanotechnology: quantum mechanical interfacing of 2D materials with biological entities (such as: bacteria, cells etc.) for functional bio-interfaces and new phenomena.

Teaching Interests:

The broad prospective of my research interests are further shaped by my recent teaching experiences. At UIC, I have developed an advanced nanoscience course ‘Graphene and Two-Dimensional (2D) Materials (ChE 494)’ from Spring 2017 and also teaching in Fall 2017. In this course, I have employed both knowledge-centered (lectures about 2D concepts) and learning-centered (2D laboratory, interactions or collaborations in a mini-2D-symposium) techniques to ensure long-term retention of fundamental concepts. In both Spring and Fall 2017, total of 40 graduate and undergraduate students are trained on emerging 2D materials theory, processing and applications. The learning goals are: 2D materials science, synthesis chemistry, nanoscale characterizations, and advanced device functionality. This course also includes laboratory demonstrations: bottom-up synthesis of graphene, its chemical transfer, and Raman spectroscopic characterizations. The student evaluation is based on conceptual quizzes, homework problems, writing a review article, and a research/project presentations. To inculcate idea of collaborations among students, I have started organizing a mini-symposium, where students have to present and interact with others fellow students. For Spring 2017, the overall teaching rating for this course is 5.00/5.00, which motivated me to further enrich the course program. For Spring 2018, I am selected to teach ‘Science and Technology of Graphene and 2D Materials (Hon 201)’ for UIC Honors College and also developing a new course ‘Photovoltaic Science and Engineering (ChE 494)’ for Spring 2018 in UIC Department of Chemical Engineering. Further as part of my outreach activity, I have delivered 8 invited lectures and 15 contributed talks at various institutions/conferences in USA, Denmark, Canada, and India. I recently received an invitation to present our ‘2D heterostructure nano-optoelectronics' work at 2017 MRS Fall Meeting, Boston in the 'Symposium NM02-Anisotropic Carbon Nanomaterials-Frontiers in Basic and Applied Research'.

Future Direction:

As an independent investigator, I would like to continue the idea of using experimental techniques and theoretical analysis to understand the structure-property correlations and diverse functionalities of 2D materials and their nanoscale attributes. In this regard, I believe the functional 2D material system I am currently focusing provides a rich experimental toolbox, with a number of fascinating and currently unexplored phenomena to reconnoiter. Potential and immediate future plan includes: (i) mechanistic understanding of charge transport at the interface of biological entities and 2D materials for bio-photovoltaics; (ii) Interfacing of 2D layers with perovskites for novel photojunctions; (iii) origami and kirigami of 2D nanocomposites and device functionality.

The distinctiveness of my methodology is the ability to develop complex 2D heterostructure circuits, characterize their structure-property correlations, and design novel energy junctions via nano-bio interfacing. Due to the highly interdisciplinary nature of my work, I envision a strong and active collaboration with fellow faculty in the university to setup specific techniques in my lab.

Selected Publications (32 total, 20 first/corresponding author, 220 citations, and 9 H-index):

S. K. Behura, P. Nguyen, R. Debbarma, S. Che, M. R. Seacrist, and V. Berry, “Chemical interaction-guided, metal-free growth of large-area hexagonal boron nitride on silicon-based substrates,” ACS Nano, Vol. 11, p. 4985-4994 (2017). Highlighted in Nature India.

S. K. Behura, P. Nguyen, S. Che, R. Debbarma, and V. Berry, “Large-area, transfer-free oxide-assisted synthesis of hexagonal boron nitride films and their heterostructures with MoS2 and WS2,” Journal of the American Chemical Society, Vol. 137, p. 13060-13065 (2015).

S. K. Behura and V. Berry, “Interfacial nondegenerate doping of MoS2 and other two-dimensional semiconductors,” ACS Nano, Vol. 9, p. 2227-2230 (2015).

S. K. Behura*, S. Nayak, I. Mukhopadhyay, and O. Jani, “Junction characteristics of chemically-derived graphene/p-Si heterojunction solar cell,” Carbon, Vol. 67, p. 766-774 (2014).
S. Che, K. Jasuja, S. K. Behura, P. Nguyen, T. S. Sreeprasad, and V. Berry, "Retained carrier-mobility and enhanced plasmonic-photovoltaics of graphene via ring-centered η6 functionalization and nanointerfacing," Nano Letters, Vol. 17, p. 4381-4389 (2017). Highlighted in Science News.

S. Deng, E. Gao, Y. Wang, S. Sen, T. S. Sreeprasad, S. K. Behura, P. Král, Z. Xu, and V. Berry, “Confined, Oriented and Electrically Anisotropic Graphene Wrinkles on Bacteria,” ACS Nano, Vol. 10, p. 8403-8412 (2016). Highlighted in The Economist.

Selected Patents (2 filed, 1 under processing of filing, 6 invention disclosures):

V. Berry, S. K. Behura, P. Nguyen, and M. R. Seacrist, “Epitaxial growth of defect-free, wafer-scale single-layer graphene on thin films of cobalt,” US Patent WO2017058928 A1, Priority Date: Oct. 1, 2015, Publication Date: Apr 6, 2017.

V. Berry, S. K. Behura, P. Nguyen, and M. R. Seacrist, “Direct formation of hexagonal boron nitride on Si-based dielectrics,” US Patent Serial Number: 62/335, 149, Filing Date: May 2016.