Light-activated photoluminescence of porous silicon

Mykola S. Boltovec, Oleksandr I. Dacenko, Svitlana M. Naumenko, Tetjana V. Ostapchuk, and Olga V. Rudenko "Light-activated photoluminescence of porous silicon", Proc. SPIE 3359, Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics 1997, (20 April 1998); https://doi.org/10.1117/12.306217

Samples ofporous silicon (PS) were etched in concentrated hydrofluonc acid. The initial and etched samples were exposed to the air by pairs at room temperature either in the dark or in daylight. In the process of exposition the integrated intensity of photoluminescence (IPL) excited by a nitrogen laser (337 nm) was measured in regular time intervals on all samples. It has been established that when samples are exposed to the light their 'PL rises with lime, increasing more rapidly in the etched samples than in the nonetched ones. 'PL of the etched samples flattened out after several weeks, while that of the nonetched ones — after several months. 'PL ofthe samples that were in the dark practically did not change with time. It is shown that the rate of 'PL nse depends on a degree of ionization of the air where the samples were located. The results obtained confirm the idea that one ofthe main factors limiting the quantum yield of PS photolurninescence is the nonradiative recombmation that results from the presence ofdangling bonds which may be saturated by the light-generated air ions.