Bronsted and Lewis base quenching of photoemission from luminescent `porous silicon': Surface protons in the luminescence mechanism

J. K M Chun, Andrew Bruce Bocarsly, T. R. Cottrell, Jay Burton Benziger, J. C. Yee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

The photoluminescence (PL) observed from porous silicon (PS) is found to be very sensitive to pH. Bronsted bases quench the PL and simultaneously produce a blue shift of the p-type PS emission. Similarly, PL of n-type PS is quenched, but the emission is red shifted. Exposure to acids enhances PL and reverses the quenching due to base exposure. A pKa of 3-4 was determined for PS formed on both n- and p-type substrates, and identifies an acidic surface proton as a primary component in the PL mechanism. Variations in the intensity and energy distribution of PL as a function of temperature suggest that: 1) small changes in the hydration state of the surface may affect the emission, and 2) at least two luminescent species exist on the surface of PS; one of which is pH and temperature sensitive. SO2, a Lewis base, also quenches the PL of p-type PS quickly and reversibly. Exposure to acid is unnecessary for restoration of the PL. In contrast to reactivity with Bronsted bases, the reversibility with SO2 argues for a different quenching mechanism. Preliminary experiments show that PL is significantly quenched, approximately 2-5%, by concentrations of approximately 30 ppm SO2 in Ar.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings
PublisherPubl by Materials Research Society
Pages329-333
Number of pages5
Volume283
ISBN (Print)1558991786
StatePublished - Jan 1 1993
EventProceedings of the Second Symposium on Dynamics in Small Confining Systems - Boston, MA, USA
Duration: Nov 30 1992Dec 4 1992

Other

OtherProceedings of the Second Symposium on Dynamics in Small Confining Systems
CityBoston, MA, USA
Period11/30/9212/4/92

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials

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    Chun, J. K. M., Bocarsly, A. B., Cottrell, T. R., Benziger, J. B., & Yee, J. C. (1993). Bronsted and Lewis base quenching of photoemission from luminescent `porous silicon': Surface protons in the luminescence mechanism. In Materials Research Society Symposium Proceedings (Vol. 283, pp. 329-333). Publ by Materials Research Society.