Optical nonlinear absorption properties of 4h-SiC-experiment and model

V. Meyers, D. Mauch, J. Dickens, A. Neuber

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Intensity-dependent nonlinear light absorption in bulk 4H-SiC at the above-bandgap energy of 3.49 eV (λ = 355 nm) is studied. Characterization and understanding of such nonlinear optical behavior in 4H-SiC forms the basis efficiency improvements and design of optoelectronic SiC devices, including photoconductive semiconductor switches. It is noted that previous research performed elsewhere had focused primarily on nonlinearities at below-bandgap energies, while little had been explored above-bandgap. In this study, absorption of short laser pulses with fluences ranging from 1 mJ/cm2 to 30 mJ/cm2 incident on 160 μm-thick high purity semiinsulating 4H-SiC samples of varying recombination lifetimes is addressed. Sample bulk recombination lifetimes vary from 0.5 ns to 100 ns displaying the range of effects from growth, electron irradiation, and annealing. The effective absorption coefficient varies significantly within this range as an apparent function of bulk recombination lifetime. A four-level time-and space-dependent finite difference time domain (FDTD) model taking into account electron trapping, interband absorption, and free-carrier absorption was constructed that yielded further insight into the absorption dynamics. For instance, the importance of free carrier absorption and deep-level trapping in the nonlinear absorption behavior is elucidated.

Original languageEnglish
Title of host publication2017 IEEE 21st International Conference on Pulsed Power, PPC 2017
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Print)9781509057481
DOIs
StatePublished - Feb 13 2018
Event21st IEEE International Conference on Pulsed Power, PPC 2017 - Brighton, United Kingdom
Duration: Jun 18 2017Jun 22 2017

Publication series

NameIEEE International Pulsed Power Conference
Volume2017-June
ISSN (Print)2158-4915
ISSN (Electronic)2158-4923

Conference

Conference21st IEEE International Conference on Pulsed Power, PPC 2017
CountryUnited Kingdom
CityBrighton
Period06/18/1706/22/17

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