Isotopic fingerprints of Pt-containing luminescence centers in highly enriched ${}^{28}\text{S}\text{i}$

Recently we have shown that the reduction in the photoluminescence linewidth of many deep luminescence centers in highly enriched ${}^{28}\text{S}\text{i}$ results in well-resolved isotopic fingerprints. This allows for a better characterization of a defect center, as not only the involvement of a specific element but also the number of atoms of that element within the complex can be determined. Surprisingly, we have found that many well-known luminescence centers have a different composition than originally supposed. In addition, we have found a large number of four- and five-atom luminescence centers involving the elements Cu, Au, and Li. Here we introduce series of four- and five-atom deep luminescence centers involving a single Pt atom together with Cu and Li, similar to what has been seen previously for Au-containing luminescence centers.

Figure 1

(Color online) Overview of the four-atom ${\left(\text{Cu},\text{Au},\text{Li}\right)}_4$ and the five-atom ${\left(\text{Cu},\text{Li},\text{Au}\right)}_5$ series in ${}^{28}\text{S}\text{i}$ at low resolution. Peaks labeled with a $\star$ are Au related centers (Ref. 10) (the ${}^{195}\text{P}\text{t}$ resulted from the decay of ${}^{195}\text{A}\text{u}$, some of which remains in the sample).

Figure 2

(Color online) The 777 meV ${\text{Cu}}_4\text{Pt}$ system. The upper spectrum shows a sample diffused with ${}^{\text{nat}}\text{C}\text{u}$. Labels 0–4 denote the number of ${}^{65}\text{C}\text{u}$ in the complex. Below this, two spectra show samples with monoisotopic Cu. The bottom two spectra show samples that have been either implanted with Pt isotopes or diffused with natural Pt. The relative intensities of the PL lines in the ${}^{\text{nat}}\text{P}\text{t}$ spectrum closely resemble the isotope abundances of natural Pt. All spectra recorded at 1.5 K and resolutions better than $1.4\mu \text{eV}$.

Figure 3

(Color online) The 884 meV ${\text{Cu}}_3\text{Pt}$ system. The upper spectrum shows a sample diffused with ${}^{\text{nat}}\text{C}\text{u}$. Labels 0–3 denote the number of ${}^{65}\text{C}\text{u}$ in the complex. Below this, two spectra show samples with monoisotopic Cu. The bottom two spectra show samples that have been either implanted with Pt isotopes or diffused with natural Pt. The ${}^{\text{nat}}\text{P}\text{t}$, ${}^{63}\text{C}\text{u}$ sample also contains a small amount of ${}^{65}\text{C}\text{u}$, slightly obscuring the spectrum. All spectra recorded at 1.5 K and resolutions better than $1.4\mu \text{eV}$.

Figure 4

Spectra of the four-atom ${\text{Cu}}_x{\text{Li}}_{\left(3-x\right)}\text{Pt}$ series in ${}^{28}\text{S}\text{i}$. Numbers from 0 to 3 designate the number of ${}^{65}\text{C}\text{u}$ atoms in the cluster, letters K, L, M, and N designate the number of ${}^7\text{L}\text{i}$ atoms in the cluster. Peaks labeled with a $\star$ are of a different, overlapping electronic state. All spectra recorded at 1.5 K and resolutions better than $1.4\mu \text{eV}$.

Figure 5

(Color online) Spectra of the four-atom ${\text{Cu}}_x{\text{PtLi}}_{\left(4-x\right)}$ series in ${}^{28}\text{S}\text{i}$. Numbers from 0 to 4 designate the number of ${}^{65}\text{C}\text{u}$ atoms in the cluster, letters K, L, M, N, and O designate the number of ${}^7\text{L}\text{i}$ atoms in the cluster. Peaks labeled with a $\star$ are of a different, overlapping electronic state. All spectra recorded at 1.5 K and resolutions better than $1.4\mu \text{eV}$.