I am a researcher at the University of Minnesota-Twin Cities, working in Prof. Chris Leighton's Semiconductor & Magnetics laboratory and working on single crystal photovoltaics. I have done my undergraduate studies in Kolkata, India with specialization in Electronics and Communication Engineering. Building-path of my academic career plays a major role in developing interest in the field of energy sustainability research. Growing up in a small town in India, taught me necessities of advancements of technology in a cost effective, and energy efficient way. A vast number of villages in India, including mine, has very limited access to electricity and modern technologies powered by it. The majority of electricity is sourced from fossil fuels causing the significant environmental damage. Being a firsthand witness of this, motivated me to search for ways to alleviate the problems and encouraged me to start my carrier where I can understand new technologies and their applications.
I started my professional career as a Lead Engineer in a solar power development industry in India, which provided me a great opportunity to experience the potential of renewable energy and its applications. This also, intrigued me to learn more about semiconductor materials and devices related to photovoltaics and I got the opportunity to experience the related research in Prof. Leighton's lab at the University of Minnesota.
R&D Test and Qualification Team Leader : Vitronics Controls
I have worked in Vitronics Controls, Pune, India which is a semiconductor power electronics industry mostly related to solar power conversion. There, I have supervised several projects related to Solar-installation and inverters. Specific skills acquired in the industry includes:
- Designing Maximum Power Point Tracking (MPPT) devices to optimize its efficiency
- Executing and troubleshooting of power inverters including solar energy conversion systems such as solar inverters and solar MPPT
- Final product quality testing of high voltage online and offline UPS and power stabilizers for industrial use and learning about their basic electronics
- Installation and maintenance of above-mentioned devices and basic knowledge on solar-panel operation
Research Experience: University of Minnesota-Twin Cities
I am currently working as a researcher in Prof. Chris Leighton's lab at the University of Minnesota. MY research involves studying single crystal Pyrite FeS2 as potential low cost solar-cell material. I am also working on understanding electronic and magnetic properties of Mott insulator NiS2 single crystals which is new expansion to our research project.
Ideally Pyrites have potential to be used for low cost, non-toxic solar cells, but surface properties hinder the possibility with poor understanding of doping controls compounding the adverse effect. In this project our team is trying to understand the root cause of these problems and developing ways to mitigate them. For example, our group recently found that the natural n-type doping in Pyrite is caused by the sulfur vacancies and is verified with varying S-vacancy doping and transport studies. Also, a different conduction type is present at the surface compared to the bulk which indicates surface carrier type is different than that in the bulk and creates an energy barrier. My research is to study this surface to bulk behavior through different doping and/or different contacts.
In the study of Mott insulator NiS2, I am trying to understand the transport and structural effect on compositional variance as well as its effect on magnetism.
Please visit our group page to learn more about the sulfide projects related to solar-cell photovoltaics.
In brief, my research skills at the University of Minnesota includes:
- High temperature growth of precursor powders of FeS2 and NiS2 which are used for chemical vapor transport (CVT) growth of single crystals useful for photovoltaics applications.
- Growth of semiconducting transition metal disulfides using CVT.
- Preparation of single crystals for characterization by mechanical polishing.
- Electronic transport measurements of photovoltaic FeS2 single crystals to study their semiconducting properties.
- Structural and compositional characterization of crystals and precursor powders using powder XRD diffraction and SEM-EDX analysis.
- Magnetometry FeS2 and NiS2 crystals to learn about their magnetic characteristics.
1) “Mitigation of the internal p-n junction in CoS2-contacted FeS2 single crystals: Accessing bulk semiconducting transport”, Bryan Voigt, Bhaskar Das, David M. Carr, Debmalya Ray, Moumita Maiti, William Moore, Michael Manno, Jeff Walter, Eray S. Aydil, and Chris Leighton, Physical Review Materials, 5, 025405 (2021).
2) “Magnetic Effect on Electron Transport in Graphene”, Bhaskar Das and Moumita Maiti, Book Chapter - Carbon Nanostructures: Fundamentals to Applications, AIP Publishing (2021).
3) “Conduction via surface states in antiferromagnetic Mott-insulating NiS2 single crystals”, Sami El-Khatib, Bryan Voigt, Bhaskar Das, Axel Stahl, William Moore, Moumita Maiti, and Chris Leighton, Physical Review Materials, 5, 115003 (2021)
4) “Observation of an Internal p–n Junction in Pyrite FeS2 Single Crystals: Potential Origin of the Low Open Circuit Voltage in Pyrite Solar Cells”, Bryan Voigt, William Moore, Moumita Maiti, Jeff Walter, Bhaskar Das, Michael Manno, Eray S. Aydil and Chris Leighton, ACS Materials Letters, 2, 861 (2020).
5) “Unconventional electronic transport near the insulator-metal transition in Co-doped pyrite FeS2 single crystals”, Bhaskar Das, Bryan Voigt, William Moore, Moumita Maiti, Vipul Chaturvedi, Greg Haugstad, Michael Manno, Eray Aydil and Chris Leighton, APS March Meeting 2022, (Manuscript under preparation).