Nikolaj Moll  Nikolaj Moll photo       

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Research Staff Member
IBM Research - Zurich
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Professional Associations:  American Physical Society (APS)  |  Deutsche Physikalische Gesellschaft (DPG)

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More information:  Nikolaj Moll - Google Scholar Citations


Structural Determination of Molecules with Atomic Force Microscopy:

research in the Computational Sciences Group and Nanoscale Sciences Group at IBM Research - Zurich

Imaging the chemical structure of molecules with atomic resolution was achieved by probing the short-range chemical forces employing noncontact atomic force microscopy. The key step to achieving atomic resolution on molecules is the functionalization of the microscope’s tip apex with suitable, atomically well-defined terminations, such as CO molecules. Density functional theory (DFT) calculations are performed to elucidate the physical origin of the observed atomic contrast. The calculations reveal that the Pauli repulsion is the source of the atomic resolution, whereas van der Waals and electrostatic forces only add a diffuse attractive background.

Polarization-Independent Photodetectors with Enhanced Responsivity in a Standard Silicon-on-Insulator Complementary Metal–Oxide–Semiconductor Process:

research in the Computational Sciences Group and I/O Link Technology Group at IBM Research - Zurich in collaboration with the University of Heidelberg

A polarization-independent photodetector device is demonstrated that can be combined with electronic integrated circuits on a single chip. The photodetector device is fully compatible with the standard silicon-on-insulator complementary metal-oxide-semiconductor (CMOS) process without requiring process modification or postprocessing.

Circular Grating Resonators as Small Mode-Volume Microcavities for Switching:

research in the Exploratory Photonics Group at IBM Research - Zurich part of the EU-Project Circles of Light

Circular grating resonators could lead to the development of very advanced silicon-on-insulator based nano-photonic devices clearly beyond state of the art in terms of functionality, size, speed, cost, and integration density. The photonic devices based on the circular grating resonators are computationally designed and studied in their functionality. A wide variety of critical quantities such as transmission and reflection, resonant modes, resonant frequencies, and field patterns are calculated. Using the computational design parameters the devices are fabricated on silicon-on-insulator substrates consisting of a buried oxide layer and a 340-nm-thick device layer. The devices are defined by electron-beam lithography and the pattern transfer is achieved in a inductively coupled reactive-ion etch process. Then the devices are characterized and as predicted the transmission spectra exhibit a wide range of different type of resonances with quality factors over 1000.

Photonic Engineering of Nonlinear-Optical Properties of Hybrid Materials for Efficient Ultrafast Optical Switching:

research in the Exploratory Photonics Group at IBM Research - Zurich part of the EU-Project Phoenix

Efficient ultrafast all-optical photonic switching elements in hybrid organic/inorganic photonic nanostructures are designed, developed and assessed. The approach encompasses all necessary components to validate this hybrid photonic switching approach: development of modelling tools, manufacturing of inorganic photonic nanostructures, advanced deposition techniques of ordered organic thin-films, and opto-electronic analysis and testing.

Photonic Crystals Based on Silicon-On-Insulator:

research in the Exploratory Photonics Group at IBM Research - Zurich in collaboration with the Watson Research Center

Optical devices based on two-dimensional photonic crystals and fabricated in silicon-on-insulator are studied theoretically and experimentally. Using photonic crystals gives the possiblity for various potential device applications to build dense optical circuits. For this the unique dispersion in photonic crystal waveguides and ultra-small microcavities in photonic crystals can be exploited.

Efficient Light Emitters Based on Photonic-Crystals-Like Structures:

research in the Exploratory Photonics Group at IBM Research - Zurich in collaboration with the Almaden Research Center

The design and fabrication of photonic-crystal-like structures using interferometric lithography and two-photon absorbtion for efficient organic light emitters. Furthermore, organic lasers are improved by incorporating a photonic crystal that consists of a thin layer of titanium-dioxide. The titanium-dioxide increases the index contrast and the confinement in the waveguideleads to a lower lasing threshold. New design criteria are investigated and employed to design an optimum organic photonic crystal laser. Devices have been fabricated according to optimum parameters and characterized.

MITite:

research in the group of J.D. Joannopoulos at MIT

A new class of semiconductors, tentatively dubbed MITite, is designed using ab-initio first principle calculations. One particular application is for monolithic integration of optical-active components with electronic devices.

Theory of the Shape and Stability of Quantum Dots on III-V Semiconductors:

research in the group of M. Scheffler at Fritz-Haber-Institute of the Max-Planck-Society

The shape and stability of Quantum Dots grown on III-V substrates is investigated combining ab-initio first principle calculations for the surface energies with finite-element calculations for the strain energies to obtain their optimum shape depending on their size.