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A view of molecular electron wavefunction through atomistic geometry of a QD bilayer; (red=In atoms, green=Ga atoms, blue=As atoms); Read full article at nanotechweb

      Muhammad Usman

          Center for Quantum Computation & Communication Technology
          School of Physics, University of Melbourne
          Parkville, 3010, Melbourne
          VIC, Australia
          Email: usman (at) alumni (dot) purdue (dot) edu

        Education & Affiliations:

          Ph.D. Electrical Engineering
          Purdue University, West Lafayette, Indiana, USA.

          M.Sc. Electrical Engineering
          University of Engineering & Technology, Lahore, Pakistan.

          B.Sc. (Honors & Distinction) Electrical Engineering
          University of Engineering & Technology, Lahore, Pakistan.

I am a member of the American Physical Society (APS), Material Research Society (MRS), IEEE, Network for Computational Nanotechnology (NCN), and Purdue Alumni Association.

Compound Semiconductor Magazine published a Feature Article in Septemeber 2013 issue on our Bismide work:
"An Elemental Change to Laser Design", Compound Semiconductor - Page 53, Volume 19, Number 6, September 2013 -
Digital copy of article is here
Corresponding editorial is here

Some of my talks are available online (more than 3500 users served @ nanoHUB.org):

[Video] Quantum Dot based Photonic Devices @ Physics Department, Dartmouth College, New Hampshire, USA

[Audio] Multi-layer QD Stacks for SOAs @ 3rd International Workshop on Epitaxial Growth and Fundamental Properties of Semiconductor Nanostructures, Austria

[Audio] Excited State Spectroscopy of a Bilayer QD Molecule @ Electrical & Computer Engineering Department, University of Iowa, Iowa, USA

[Audio] Theory of Bismide Alloys @ 2nd International Workshop on Bismuth containing Semiconductors, Surrey University, UK

[Audio] Why QD Simulations Must Contain Multi-Million Atoms?  

[PDF] PhD Research Summary @ Purdue University, Indiana, USA

[PDF] Quantum Dots - My PhD Thesis @ Purdue University, Indiana, USA


Multi-Scale Modeling; Condensed Matter Physics; Atomistic Modeling; III-V Materials; Semiconductor Heterostructures; High Performance Computing; NEMO 3-D; Optoelectronic Devices; Valence Force Field Model; Tight Binding Theory; Quantum Dots; Electronic Structure and Quantum Transport Calculations in Nanoscale Devices; Quantum Mechanics; Novel Bismuth based Alloys; Electronic Structure of Disordered Semiconductors; Theory of Iso-electronic Impurities;

Research Interests:

I work in multi-disciplinery area of research involving rigorous knowledge of nano-electronics, condensed-matter physics, computational physics, etc. Overall, I am interested in all aspects of light matter interaction. My research work is aimed at improving the efficiency of the energy-conversion devices (photovoltaics), wavelength and polarization engineering by studying novel nano-materials for telecomm and infra-red range devices, and quantum information science in coupled quantum dot systems.

More specifically, I work on the theory, modeling, and simulation of semiconductor materials, their alloys, and low-dimensional devices.

My past and ongoing research efforts are motivated to seek answers for the following questions:

  • Can we design efficient photonic devices from quantum dots? How can we engineer QD parameters to tune output wavelength and polarization for a desired operation?

  • How can bismuth (Bi) based alloys such as GaBiNAs, InGaBiAs, etc. help to realize highly efficient telecomm wavelength devices with reduced temperature sensitivity and supressed Auger losses?

  • How to implement qubit operation in a coupled quantum dot system via coherent manipulation of the trapped charges or spin?

  • To understand and resolve efficiency impeding mechanisms in nanomaterial based photovoltaics to realize sustainable, ecnomical, efficient, and green energy solutions

  • My theory and modeling work is based on the following methods:

  • Strain energy minimization by using atomistic valence force field method.

  • Electronic structure calculations based on twenty/ten bands sp3d5s*/sp3s* Tight Binding method, 14 bands k.p models, DFT.

  • Optical transition strengths from the Fermi's Golden Rule.

  • Linear and quadratic piezoelectric potentials by solving the Poisson's equation.

  • Many-body excitonic spectra by Hartree-Fock (HF) Approximation, Configuration Interaction (CI) approach

  • The detials about these methods are presented here: Modeling Methodologies   

    My current and past experimental collaborators are at:

    I want to acknowledge support from the following organizations:

                                                  Last updated: August 2012, (best viewed in chrome browser), copyright © Muhammad Usman, all rights reserved.