Blue electroluminescence from high dose Si  implantation in SiO 2 D. Muller a, * , P. Kn apek b , J. Faur e c , B. Prevot a , J.J. Grob a , B. H onerlage d , I. Pelant b a Laboratoire PHASE, UPR 292 ± CNRS, 23 rue du Loess, 67037 Strasbourg Cedex, France b Institute of Physics AVCR, Cukrovarnicka 10, 162 53 Praha 6, Czech Republic c Laboratoire de Microscopie Electronique UTAP, 51685 Reims Cedex 2, France d IPCMS-GONLO, UMR 7504 CNRS-ULP-ECPM, 67037 Strasbourg Cedex, France Abstract Many results have been obtained on the photoluminescence (PL) properties of Si nanocrystals embedded in SiO 2 but very few about electroluminescence (EL) of Si/SiO 2 implanted layers. Thermally grown SiO 2 layers on Si have been implanted with high doses of Si  and annealed at high temperature. Complementary techniques were used to char- acterize this structure. The implanted Si atomic distribution was determined by Rutherford Backscattering (RBS) measurements whereas the crystallinity of the layer was investigated by Raman scattering and XTEM. In particular, it was observed that Si nanocrystals, with typical dimensions larger than 10 nm, have been formed after the annealing step. A blue room-temperature EL (narrow peak at around 470 nm) was observed at high electrical ®elds. This study points out the importance of the capability of the electroluminescent structure to produce hot electrons. Ó 1999 Elsevier Science B.V. All rights reserved. PACS: 78.60.Fi; 85.40.Ry; 61.46.+w; 73.61.Tm Keywords: Electroluminescence; Ion implantation; Si nanocrystals 1. Introduction An intense activity on the luminescence prop- erties of silicon based structures has appeared since the discovery of visible light emission at room temperature in porous silicon [1]. After that, a lot of other materials and devices were investigated. Among them structures based on Si nanocrystals have stimulated considerable research in under- standing the optical properties and their optimi- sation towards possible applications. Initial results showed the importance of the quantum con®ne- ment eect [1] and the surface states [2,3] of the low dimensional structures. Recently, the fabrica- tion of Si nanocrystals embedded in silicon oxide has led to some interesting results [3±8]. One of the promising techniques used to elab- orate such materials is the implantation of Si ions into SiO 2 grown by thermal oxidation of silicon. Despite the low electroluminescence (EL) ecien- cy of such devices up to now, they oer the ad- vantage of being completely compatible with the Nuclear Instruments and Methods in Physics Research B 148 (1999) 997±1001 * Corresponding author. Tel.: +33 03 88 10 66 93, fax: +33 03 88 10 62 93;; e-mail: mullerd@phase.c-strasbourg.fr 0168-583X/98/$ ± see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 8 ) 0 0 6 7 7 - 6