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Science 3 November 1995:
Vol. 270. no. 5237, pp. 776 - 778
DOI: 10.1126/science.270.5237.776
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Reports

Photoluminescence from Porous Silicon by Infrared Multiphoton Excitation

R. P. Chin,  Y. R. Shen (1),  V. Petrova-Koch

Visible photoluminescence from porous silicon induced by infrared multiphoton excitation was observed at room temperature. Luminescence resulted from carrier excitations in the surface region of the sample. With the pump in the mid-infrared, excitation was effective only when the pump frequency was near resonance with the stretch vibrations of the surface species, SiH. For each visible photon emitted, at least seven or eight infrared photons were absorbed. The excitation is believed to occur via pumping up a vibrational ladder, followed by conversion to electronic excitation. The process is similar to infrared multiphoton excitation of polyatomic molecules.


R. P. Chin and Y. R. Shen, Department of Physics, University of California, Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA 94720, USA.
V. Petrova-Koch, Department of Physics and Department of Chemistry, Technische Universität München, 85747 Garching, Germany.
(1) To whom correspondence should be addressed.

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Science. ISSN 0036-8075 (print), 1095-9203 (online)