Multimodal luminescence spectra of ion-implanted silica

Abstract

Main luminescence bands in silica SiO 2 are the red luminescence R (650 nm, 1.9 eV) of the non-bridging oxygen hole center, the blue band B (460 nm, 2.7 eV) and the altraviolet luminescence UV (290 nm, 4.3 eV) both related commonly to oxygen deficient centers. In the present work we will enhance or replace either the first or second constituent of SiO 2 , i. e. silicon or oxygen, isoelectronically by additional implantation of respective ions. Thus thermally oxidized SiO 2 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 5 · 10 16 cm −2 leading to an atomic dopant fraction of about 4 at% at the half depth of the SiO 2 layers. Very surprisingly, the cathodoluminescence spectra of oxygen and sulfur implanted SiO 2 layers show besides characteristic bands a sharp and intensive multimodal structure beginning it the green region at 500 nm up to the near infrared. The energy step differences of the sublevels amount in average 120 meV and indicate vibration associated electronic states, probably of O − 2 interstitial molecules.

Concentration and Annealing Effects on Luminescence Properties of Ion-Implanted Silica Layers

“…Moreover, the sharp and intense multiple peaks in the region 1.5-2.48 eV are observed for these layers as in O + implanted layers both for room temperature and liquid nitrogen temperature with higher intensity. The exact band positions correspond to almost equidistant energy steps of 140 meV in the green region then slightly decrease to 110 meV in the IR region, as we have already described in [18,19]. Thus the mean energy step width is about 120 meV.…”

“…As a surprising peculiarity, the cathodoluminescence spectra of oxygen-and sulfur-implanted SiO 2 layers show a sharp and intensive multimodal structure between 1.5 eV and 2.48 eV. The energy step differences of the sublevels amount to an average of 120 meV and indicate vibronicelectronic transitions, probably, of O 2 − interstitial molecules, as we could demonstrate by a respective configuration coordinate model [19,24].…”

Synthesis and optical properties of amorphous C–Si–O particles

“…We consider that the four PL peaks are assigned to certain oxygen defects in the particles and the surface-state of the particles. There have been many studies on the PL of the amorphous silicon nanomaterials, such as silica nanowires [43,44], silica glass [45], silica layers [46,47] ionimplanted silica [48], etc. Various silica glasses and nanowires show luminescence bands with different peak energies ranging from 1.9 to 4.3 eV [43][44][45][46][47][48].…”

“…There have been many studies on the PL of the amorphous silicon nanomaterials, such as silica nanowires [43,44], silica glass [45], silica layers [46,47] ionimplanted silica [48], etc. Various silica glasses and nanowires show luminescence bands with different peak energies ranging from 1.9 to 4.3 eV [43][44][45][46][47][48]. Those peaks arise from particular defects centers including the Si related oxygen deficient center (SiODC) with the blue (460 nm; 2.7 eV) and ultraviolet UV band (295 nm; 4.2 eV) [49,50], the self trapped exciton (STE) with the yellow-green luminescence at 580 nm (2.1 eV) [51] and the nonbridging oxygen-hole center (NBOHC: Si Á O Á ) associated with the red luminescence at 650 nm (1.9 eV) [52].…”

Plasma-enhanced chemical vapor deposition of silicon dioxide

“…They could remain from the diffusion of oxygen through SiO 2 towards the interface of the Si substrate, in line with the Beck-Majkusiak model. Salh, Von Czarnowski, and Fitting have studied over-stoichiometric SiOx by cathodoluminescence (CL) [173,218,219]. To do so, they implanted dry oxidized SiO 2 layers additionally by O + ions.…”