IISER Bhopal researchers conduct study on nature of charge carriers in metal dichalcogenides

NEW DELHI: Researchers at Indian Institute of Science Education and Research (IISER) Bhopal are conducting research on properties of transition metal dichalcogenides (TMDs), a class of advanced two-dimensional materials. The research is being led by KV Adarsh, professor at physics department of IISER Bhopal and his co-workers.

Findings of the research have already been published in the journal of Physical Chemistry C, and surface and interface analysis. A statement from the institute said that the research being conducted on one kind of TMDs, named Molybdenum disulphide nanosheets, could pave the way for development of optoelectronic devices such as solar cells, light emitting diodes (LEDs), and phototransistors. Researchers of IISER Bhopal and of Bhabha Atomic Research Centre (BARC) Mumbai used an advanced technique called femtosecond transient absorption spectroscopy, to study how light interacts with molybdenum disulphide nanosheets.

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Research findings

In the research, it was inferred that two types of charge particles, excitons and free carriers, behave differently on the basis of the amount of energy used to excite them. Researchers concluded that the high-energy light produces excitons and free carriers, but the excitons disappear quickly due to defects. On the other hand, the Free carriers lingered on for a nanosecond.

"Our systematic studies in few-layer Molybdenum disulphide nanosheets reveal crucial information about the unexplored domains of excitons and free carriers' recombination in the presence of defects for several optoelectronic applications", head of the research, KV Adarsh said.

He added that they have also examined the characteristics of defects and have also studied various configurations of sulphur vacancies using density functional theory (DFT) and time dependent DFT.