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In recent years, there has been a surge in interest in the development of unique
opto-electronic semiconductors for solar cells, photo detectors, LEDs, and other
applications. Light and electricity are converted into one another via photo-excited
carrier generation and carrier recombination in these materials. The dynamics of
the photo-excited carriers are used to evaluate the performance of these materials
in optoelectronic devices. However, it is widely known that trapping of charge
carriers influences the dynamics of photoexcited carriers. The trapping might be
caused by intrinsic trapping, such as self-trapping (polarons and excitons), or by
the extrinsic defects (oxygen vacancies). Also, the trapping of carriers can occur in
ultrafast time scales which can be probed by using ultrafast time resolved pump
probe spectroscopy. In this talk, I shall discuss the photoexcited carrier dynamics
associated with the various trapping mechanisms studied using non-degenerate
pump-probe spectroscopy.
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