Abstract
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.PACS78.55.Mb; 78.67.Rb; 78.47.jd
Highlights
The efficient room-temperature visible photoluminescence (PL) from porous silicon (PSi) has attracted much attention in recent years, mainly due to open questions and controversies concerning the mechanism responsible for the PL emission [1,2,3,4,5,6,7]
We examine the extended vibron (EV) model by comparing radiative and nonradiative decay times of freshly prepared hydrogen-terminated PSi (H–PSi), with those of oxidized PSi (O–PSi)
Utilizing temperature-dependent, time-resolved PL (TR-PL) spectroscopy [42], we extend our previous work on silicon nanocrystals embedded in SiO2 matrices and silicon nanowires [37,41,43,44] to PSi, as this system allows a modification of the surface chemistry by simple means and tracing quite accurately the state of the surface
Summary
The efficient room-temperature visible photoluminescence (PL) from porous silicon (PSi) has attracted much attention in recent years, mainly due to open questions and controversies concerning the mechanism responsible for the PL emission [1,2,3,4,5,6,7]. PSi has been considered as an attractive candidate for sensing applications [16,17,18,19,20,21] where its large surface area can be exploited for enhancing the sensitivity to surface interactions. In such a sensor, the PL emitted from PSi can be used as a transducer that converts the chemical interaction into a measurable optical signal. The efficient PL from PSi was attributed to quantum confinement (QC) of charged carriers in Si the surface chemistry. Both QC and surface chemistry contribute to the efficient PL from PSi
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call