Radiative and nonradiative relaxation phenomena in hydrogen- and oxygen-terminated porous silicon
Racah Institute of Physics and the Harvey M. Kruger Family Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
Nanoscale Research Letters 2014, 9:47 doi:10.1186/1556-276X-9-47Published: 28 January 2014
Using time-resolved photoluminescence spectroscopy over a wide range of temperatures, we were able to probe both radiative and nonradiative relaxation processes in luminescent porous silicon. By comparing the photoluminescence decay times from freshly prepared and oxidized porous silicon, we show that radiative processes should be linked with quantum confinement in small Si nanocrystallites and are not affected by oxidation. In contrast, nonradiative relaxation processes are associated with the state of oxidation where slower relaxation times characterize hydrogen-terminated porous silicon. These results are in a good agreement with the extended vibron model for small Si nanocrystallites.
78.55.Mb; 78.67.Rb; 78.47.jd