Principal Investigator Chennupati Jagadish Project u58

Electronic Materials Engineering, Machine CM

Research School of Physical Sciences and Engineering

Co-Investigators A Krotkus, H H Tan,

Electronic Materials Engineering, Research School of Physical Sciences and Engineering


Molecular Dynamics Simulation of Carrier Dynamics in Semiconductors

Study of carrier dynamics of photoexcited carriers is of importance to understand carrier trapping processes in non-stoichiometric III-V compound semiconductors. Aim of the project is to create ultrashort lifetime materials for fast photodetector applications. In order to understand experimental results, molecular dynamics simulations of carrier dynamics in these semiconductors is essential.


What are the basic questions addressed?

Ultrafast photoexcited carrier dynamics in GaAs.

What are the results to date and future of the work?

Dynamics of the photoexcited carriers in non-stoichiometric GaAs (including ultrafast carrier trapping) were simulated.

Carrier distribution functions were calculated at various times after photoexcitation, photoluminescence spectra and photoluminescence transients at various excitation and trapping rates and these were compared with experimentally observed photoluminescence transients. Futher simulations are necessary to understand experimental observations.

What computational techniques are used and why is a supercomputer required?

Monte Carlo/Molecular Dynamics techniques for used for simulations. These techniques (particularly molecular dynamics) are very CPU time intensive and these could only be achieved on supercomputers such as CM-5.

Publications

Non-Thermal photoexcited electron distributions in non-stoichiometric GAAs, S. Marcinkevicius, R. Viselga, A. Krotkus, U. Olin, H. H. Tan and C. Jagadish, Phys. Rev.Lett. (Submitted)