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Bipin Kumar Gupta

Publications and source records attributed to Bipin Kumar Gupta.

2 recordsLinked to original sources

Quantum Dot Moir\'e from Crossed MoS2 Nanoribbons

Twisted atomically thin layers have attracted much attention for Moir\'e potential and correlated quantum phenomena. However, existing Moir\'e superlattices have largely been limited to extensive wavefunction without lateral confinement. Here we introduce a new platform where 1D nanoribbons of 2D MoS2 grown by vapor deposition can be easily superposed at various angles from stacking and transferring, to form Moir\'e quantum dots at their intersections with unique exciton physics. Angle-dependent Moir\'e intersections show enhanced exciton emission at commensurate angle 22 deg, which demonstrates faster relaxation at the cryogenic temperature. A size-dependent study further exhibits a reduced exciton energy and soften out-of-plane interlayer coupling for smaller Moir\'e areas. Our results reveal exciton physics turnability via precise overlapping of 1D nanoribbons.

cond-mat.mtrl-sci

Unexplored photoluminescence from bulk and mechanically exfoliated few layers of Bi2Te3

We report the exotic photoluminescence (PL) behaviour of 3D topological insulator Bi2Te3 single crystals grown by customized self-flux method and mechanically exfoliated few layers (18 plus minus 2 nm)/thin flakes obtained by standard scotch tape method from as grown Bi2Te3 crystals.The experimental PL studies on bulk single crystal and mechanically exfoliated few layers of Bi2Te3 evidenced a broad red emission in the visible region. These findings are in good agreement with our theoretical results obtained using the ab initio density functional theory framework.

cond-mat.mtrl-sci