Can highly enriched 28Si reveal new things about old defects?

Isotopic fingerprints of Pt-containing luminescence centers in highly enrichedS28i

“…abundances before enriched Cu diffusions were performed, it later showed slightly different ratios due to contamination of the furnace and quartzware. When diffusing a single isotope into a sample we have in most cases reached a very high degree of enrichment, especially for Cu and 7 Li, where the starting materials were very highly enriched, and in the case of 7 Li, any contamination with background nat Li is already mostly 7 Li. However, a fine balance between diffusing a sufficient amount of one isotope and oversaturating the sample had to be found.…”

“…However, a fine balance between diffusing a sufficient amount of one isotope and oversaturating the sample had to be found. In the case of 6 Li, a considerable amount of 7 Li remained visible in most spectra due to both the lower enrichment of the starting material and the dominance of 7 Li in any contamination from background nat Li. Hence the 6 Li enrichment in our samples sometimes only amounts to ϳ80%.…”

“…These results span the fields of shallow [1][2][3] and deep 4 impurity infrared-absorption spectroscopy, shallow bound exciton ͑BE͒ photoluminescence ͑PL͒ and photoluminescence excitation spectroscopy, 2,5,6 and deep center PL spectroscopy. [7][8][9][10] For the deep PL centers, often referred to as isoelectronic BE due to their relatively large PL efficiency compared to shallow donor and acceptor BE in Si, these reduced linewidths have resulted in a new and powerful method of characterizing the constituents of the binding center. [7][8][9][10] While isotope shifts have been an established method for the investigation and identification of such deep PL centers for many years, 11 the observed shifts of the PL lines have typically been smaller than the spectroscopic linewidths, revealing the participation of a given element in the center but not the number of atoms of that element.…”

“…[7][8][9][10] For the deep PL centers, often referred to as isoelectronic BE due to their relatively large PL efficiency compared to shallow donor and acceptor BE in Si, these reduced linewidths have resulted in a new and powerful method of characterizing the constituents of the binding center. [7][8][9][10] While isotope shifts have been an established method for the investigation and identification of such deep PL centers for many years, 11 the observed shifts of the PL lines have typically been smaller than the spectroscopic linewidths, revealing the participation of a given element in the center but not the number of atoms of that element. By making use of the dramatically narrower spectroscopic linewidth of no-phonon ͑NP͒ PL transitions in isotopically enriched 28 Si together with a highresolution spectrometer, PL peaks due to combinations of different isotopic masses of the constituents of a complex can be fully resolved, resulting in an "isotopic fingerprint" of the defect constituents.…”

Cu complex in silicon and its photoluminescence

“…In this situation, it is our surprise to see that a completely different picture came out by a study of Thewalt group on the isotope shift of the ZP line [6,7,8]. By using highly enriched 28 Si to eliminate the inhomogeneous isotope broadening, they have succeeded to resolve the Γ 3 and Γ 4 peaks of the Cu 0 0 line, and more importantly to show that each peak has fine structures.…”