Three dimensional (3D) topological insulators (TIs) like bismuth selenide (Bi2Se3) are unique set of quantum materials that hold potentials for realizing Majorana Fermions and spintronics applications. Electrons at the metallic surface states of Bi2Se3 are spin textured and are immune to non-magnetic impurity backscattering. The extraordinary properties of Bi2Se3 can be modified by reducing the size of nanostructure, changing the shape and injecting carriers into the metallic surface states of Bi2Se3. The interplay between the interaction of the injected carriers and phonons in Bi2Se3 is studied with a nanoscopic Raman. We developed a nanoscopic Raman with beam spot size of ≈ 211 nm to reveal locally resolved information about charge transfer onto the metallic surface states of Bi2Se3. Geometrical two-dimensional (2D) nanoflakes (NFs) of Bi2Se3 on gold (Au) substrate reveal interface-enhanced Raman scattering, broadening of phonon linewidth and strong phonon renormalization induced by carriers injected from the Au substrate to the Bi2Se3 surface states. Geometrical confinement of Bi2Se3 cylindrical nanowires (NWs) from 2D limit to 1D result in splitting of the metallic surface states into sub-bands, opening of a gap at the Dirac point and lifting of the non-degenerate surface states because of a π-Berry Phase effect. Magnetic field of flux ratio r = 0.5 applied along the axis of Bi2Se3 NW nullifies the effect of the π-Berry Phase and thus closes the gap at the Dirac point (i.e. restores the non-degenerate surface states). The 2D to 1D crossover in Bi2Se3 cylindrical nanowire below 50 nm radius is marked by sudden appearance of plasmonic surface-enhanced Raman scattering (SERS) which dominates the electronic excitation spectrum. In plasmonic Au nanoparticles (AuNPs) injecting hot carriers into the Bi2Se3 nanoribbons (NRs) we report enhancement of phonon modes which is dependent on the excitation wavelength and the distance within the vicinity of AuNP. In resonance at 633 nm excitation wavelength and on 108 nm ...