Santu Kumar Bera

Indian Institute of Science Bangalore | IISC · Department of Physics

Charge separation and many-body interactions at the interface of the light-absorbing semiconductor and contact layer are of crucial importance to the photophysical properties and optoelectronic device performance. Here, we report the exciton many-body interactions and charge transfer dynamics at the interface of metal halide perovskite nanocrystals...

Auger recombination and thermalization time are detrimental in reducing the gain threshold of optically pumped semiconductor nanocrystal (NC) lasers for future on-chip nanophotonic devices. Here, we report the design strategy of facet engineering to reduce the gain threshold of amplified spontaneous emission by manyfold in NCs of the same concentra...

We demonstrate dynamical photo-physics of shape-engineered cube (6 facets), rhombic-dodecahedron (12 facets), and rhombicuboctahedron (26 facets) CsPbBr 3 nanocrystals using ultrafast pump-probe spectroscopy. Results show remarkably contrasting carrier dynamics and Burstein-Moss effect for tuning optoelectronic properties.

Coulomb interactions in atomically thin transition metal dichalcogenides can be dynamically engineered by exploiting the dielectric environment to control the optical and electronic properties. Here we demonstrate an optically tunable giant band-gap renormalization (BGR) ∼1200 and 850 meV from the edge of the conduction band and complete suppressio...

Atomically thin transition metal dichalcogenides (TMDCs) have emerged as a leading semiconductor over the past decades due to their exceptional electronic, optoelectronic and quantum properties. Here, we have studied tuning of optical and electronic properties in CVD grown single- and few-layer MoS2 by employing spectrally and temporarily resolved...

We demonstrate layer-engineered crossover of relaxation pathways from fast exciton- exciton annihilation in monolayer to slow phonon bottleneck in few-layer MoS 2 . Our study reveals new, layer degree of freedom to tune ultrafast dynamics in optoelectronic applications.

Realization of the direct charge transfer at metal-semiconductor interfaces is a long-standing goal of both fundamental and technological significance. Here we report the synthesis of colloidal Sb2Se3-Au core-shell nanorod (CSNR) as a model system to demonstrate an efficient direct charge transfer from Au shell to Sb2Se3 core when selectively excit...

We study experimentally and theoretically the intensity-dependent off-resonant ultrafast third-order nonlinear optical response of As 2 S 2 thin films. At low intensity, we observed saturable absorption with a negative (self-defocusing) nonlinear refractive index ( n 2 ) which at higher intensity switched over to reverse saturable absorption with a...