Myself Dipak Kumar Goswami
Max Planck Institute for Metals Research
Heisenbergstraße 3
D-70569 Stuttgart, Germany
Email: xdipak@gmail.com


Designed & Maintained:
Dipak K Goswami
Controlled Evolution Of Polymer Single Crystal
    Dip-pen-nanolithography (DPN) technique is normally used as a technique to pattern the substrate surface using molecular solution. Here AFM tip is used as nib and molecular solution is used as ink. We have used DPN technique as a tool to initiate and control the polymer single crystal growth. Poly-DL-Lysine hydrobromide (PLH) molecules have been deposited on freshly cleaved mica (001) surfaces through the AFM tip. PLH molecules grow as triangular prisms following the symmetry of the underlying mica (001) lattice. Using grazing incidence oscillation X-ray diffraction measurement we proved that these prisms are single crystal in nature and from back reflection Laue we determined their relative orientation with respect to underlying mica lattice.
Science, 2005, Chemical & Engineering: Latest News, March 23, 2005


RT growth Of Ag/Si(111): STM and STS Study
    Room temperature (RT) growth of Ag nanostructures on Si(111)-7x7 were studied during my Ph.D. work. We have observed that Ag grows as plateaulike islands with strong preference of two atomic layers height at RT. Ag continues to grow with an even layer height preference at higher coverage. Quantum size effect (QSE) due to spatial confinement of electrons in thin films appears to play an important role in this growth mechanism. This introduces discrete quantum well states (QWSs) inside the metal films. This drives the stability of the film. We have observed single electron tunneling (SET) effect on the individual Ag island at 100 K substrate temperature using scanning tunneling spectroscopy (STS) measurement. The effect of quantum capacitance on the Coulomb staircase has been explained.
Cond-mat/0311506, 2003


Effect of Nanoscale Surface Morphology On Growth
    We have observed nanoscale surface smoothing on MeV ion bombarded silicon surfaces and determined the roughness scaling exponent for such smooth surfaces by STM. These surfaces are self-affine fractal in nature. The adhesion of a deposited material on fractal surface strongly depends on fractal dimension (i.e. nanoscale surface morphology). We have produced surfaces with different fractal scaling exponent using ion bombardment technique and studied the self-assembled growth of Ge on those surfaces. Self-assembled growth of Ge on fractal surfaces is significantly influenced by the nanoscale surface morphology.
Phys. Rev. B, 2003; NIM B, 2003, Surf.Sci. 2004