Photoluminescence of Se-related oxygen deficient center in ion-implanted silica films

Journal of Applied Physics

Onge

et al. 2014

Cobalt and manganese ions are implanted into SiO 2 over a wide range of concentrations. For low concentrations, the Co atoms occupy interstitial locations, coordinated with oxygen, while metallic Co clusters form at higher implantation concentrations. For all concentrations studied here, Mn ions remain in interstitial locations and do not cluster. Using resonant x-ray emission spectroscopy and Anderson impurity model calculations, we determine the strength of the covalent interaction between the interstitial ions and the SiO 2 valence band, finding it comparable to Mn and Co monoxides. Further, we find an increasing reduction in the SiO 2 electronic band gap for increasing implantation concentration, due primarily to the introduction of Mn-and Co-derived conduction band states. We also observe a strong increase in a band of x-ray stimulated luminescence at 2.75 eV after implantation, attributed to oxygen deficient centers formed during implantation.

Section: Luminescencesupporting

confidence: 83%

Section: Luminescencesupporting

confidence: 62%

Electronic band gap reduction and intense luminescence in Co and Mn ion-implanted SiO2

Green

Journal of Applied Physics

Onge

et al. 2014

“…The relatively low contribution of Re-metal XPS signal into Re 4f core-level spectra for these samples does not contradict the offered interpretation for the appearance of wide-and-broad shoulder located at the vicinity of E F and well coincides with the fluence dependence of spectral features reported and discussed above. We suppose that rhenium oxide phases are also contributing to the VB structure of the samples under study but actually their contribution is not essential even in core-levels (see Fig.2 [32,33] which is well-detected by a luminescence spectroscopy technique (will be the subject of our posterior separate and extended study). Returning back to the discussion of Reembedding scenarios into KUVI-SiO 2 , one can suppose the [Re 4+ + vO 0 (≡Si-Si≡)] → Si 4+ mechanism of quazi-isovalence substitution.…”

Section: Resultsmentioning

confidence: 98%

The MRO-accompanied modes of Re-implantation into SiO2-host matrix: XPS and DFT based scenarios

Journal of Alloys and Compounds

Boukhvalov

et al. 2017

Self Cite

The following scenarios of Re-embedding into SiO 2 -host by pulsed Re-implantation were derived and discussed after XPS-and-DFT electronic structure qualification: (i) low Re-impurity concentration mode → the formation of combined substitutional and interstitial impurities with Re 2 O 7 -like atomic and electronic structures in the vicinity of oxygen vacancies; (ii) high Reimpurity concentration mode → the fabrication of interstitial Re-metal clusters with the accompanied formation of ReO 2 -like atomic structures and (iii) an intermediate transient modewith Re-impurity concentration increase, when the precursors of interstitial defect clusters are appeared and growing in the host-matrix structure occur. An amplification regime of Re-metal contribution majority to the final Valence Band structure was found as one of the sequences of intermediate transient mode. It was shown that most of the qualified and discussed modes were accompanied by the MRO (middle range ordering) distortions in the initial oxygen subnetwork of the a-SiO 2 host-matrix because of the appeared mixed defect configurations. IntroductionKnown since ancient times, amorphous silicon dioxide (a-SiO 2 ) still remains of great importance for various high-tech applications because of the powerful technological potential. Having good chemical stability in the wide range of temperatures and relatively aggressive ambients, it was deeply studied since the beginning of the 20 th century, causing the successful yield of cheap and, simultaneously, effective commercial and semi-commercial synthesis approaches ("wet", "dry" or combined "wet-and-dry" technology [1], several variations of CVD [2], aerogel [3], nanosized synthesis [4], etc.). This technologically important material has found also an extended functionality due to applied electronic structure engineering trends and controlled management of the needed functional properties via atomic structure conversion mechanisms [5-7]. Advisability of a-SiO 2 as a material for managed atomic structure conversion is determined by the peculiarities of ≡ Si -O * chemical bonding unit. This major silicon-oxygen bonding unit arises due to σcoupling of Si s-and Si p-electrons with oxygen p-electrons, but, as a unique specificity, the short and elonged (O 2p -Si 3d) π conjugations are possible. Consequently, it is potentially giving the most wide set of dihedral angles as well as the variations in silicon-oxygen bonding distance with a critical border-values of 1.54 Å and 1.81 Å [8]. As a result, a lot of silica-oxygen polymorphs with dissimilar physical-chemical properties exist (see e.g. Ref. [6]), providing favorable conditions for the further elaboration within Research-and-Development area of SiO 2 -based functional materials. Despite of the powerful technological suit for electronic structure functionalization of a-SiO 2 via conventional embedding of metal or metal-like particles into Zachariasen-Warren threedimensional glassy network, the direct ion-doping by ion-implantation techniques was proved to be promisin...

“…At the same time nanostructured silicon dioxide layers are of great interest as active waveguide elements for modern microand optoelectronics. Their modification by ion-beam synthesis offers the prospect of creating microminiature light sources and optical switchers [6]. The variety of possible bond types between the atoms of silicon, oxygen, and lead determines the features of luminescence and optical properties of such systems [7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…The peculiarities of modification of the SiO 2 implanted with IV and VI group ions and properties of point defects formed during implantation were studied in our previous papers: [13,14] (Si + ions), [15] (Ge + implantation), [16] (Sn + bombardment), [17,18] (selenium ions) and [19] (sulfur). The present article is devoted to the study of the energy structure of luminescence centers in the silica films and glasses implanted with lead ions by means of low-temperature time-resolved photoluminescence excited by synchrotron radiation pulses.…”

Section: Introductionmentioning

confidence: 99%

Defects and localized states in silica layers implanted with lead ions

Journal of Luminescence

Fitting

Бунтов

et al. 2014

Self Cite

The luminescence of silica films and glasses implanted with Pb + ions was studied by means of time-resolved photoluminescence spectroscopy under synchrotron excitation. The ion-modified silica layers are "metal-dielectrics" composites the oxide part of which is represented by amorphous micro-heterogeneous phase with variable Pb 2+ ions. Two groups of emission centers are identified: such as: (1) radiation-induced oxygen-deficient centers (ODCs) and non-bridging oxygen atoms (NBOs) in the SiO 2 matrix and (2) localized electronic states (LS) of the amorphous lead-silicate phase.