Research Projects

Two-dimensional nanomaterials, originating from atomic 2D crystals, are a promising platform for scientific and technological advancements. Transition metal dichalcogenides (TMDs) and their heterostructures are highly promising lasing materials due to their intra/interlayer excitons and high radiative recombination rate. These excitons show considerable binding energy up to 1 eV, allowing high Mott transition density. When TMDs thinned down from bulk to monolayer, their bandgap increases, resulting in a significant enhancement of PL efficiency. However, these materials cannot be directly used as laser sources due to their incoherent light emission. This proposal focuses on coupling TMDs exciton emission with high-quality photonic cavities through material engineering for coherent light amplification and fabrication of ultracompact nanolasers. Integrating the TMD material with a photonic cavity helps confine the excitonic emission, producing stimulated emission via Purcell enhancement. To exploit the maximum spontaneous emission of the active medium, the resonant mode of the cavity must overlap with the exciton wavelength. To reduce mode leakage, a saturable absorber material such as graphene or suitable 2D material will be placed on top of the active medium. The aim is to produce ultracompact and low threshold lasers with high output power using this approach. The fabricated device will also be tested for photodetector, phototransistor, and optical modulator applications for on-chip photonics.

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