Multimodal Luminescence Spectra of Ion-Implanted Silica


Multimodal Luminescence Spectra of Ion-Implanted Silica

Fitting, H.-J.; Salh, R.; Schmidt, B.

The main luminescence bands in silica SiO2 are the red luminescence R (650 nm, 1.9 eV) of the non-bridging oxygen hole center, and the blue band B (460 nm, 2.7 eV) and ultraviolet luminescence UV (290 nm, 4.3 eV), both commonly related to oxygen-deficient centers. In the present work, we will enhance or replace either the first or second constituent of SiO2, i.e., silicon or oxygen, isoelectronically by additional implantation of the respective ions. Thus, thermally oxidized SiO2 layers have been implanted by different ions of the IV group (C, Si, Ge, Sn, Pb) and of the VI group (O, S, Se) with doses up to 5x1016 cm-2, leading to an atomic dopant fraction of about 4 at % at the half depth of the SiO2 layers. Very surprisingly, the cathodoluminescence spectra of oxygen- and sulfur-implanted SiO 2 layers show, besides the characteristic bands, a sharp and intensive multimodal structure beginning at the green region at 500 nm up to the near infrared. The energy step differences of the sublevels equal on average 120 meV, and indicate vibration associated electronic states, probably of O2- interstitial molecules.

Keywords: Cathodoluminesence; silicon dioxide; ion implantation

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Publ.-Id: 9658