Physica E 8 (2000) 365–368 www.elsevier.nl/locate/physe Ultra-stable visible electroluminescence from crystalline-Si= O superlattice Q. Zhang a ; * , A. Filios a , C. Lofgren a; b , R. Tsu a a Department of Electrical Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223, USA b NanoDynamics Inc. New York, NY 10021, USA Accepted 4 November 1999 Abstract We report an extremely stable electroluminescent device utilizing a crystalline Si= O superlattice, grown by molecular beam epitaxy with in situ oxygen exposure. Oxygen exposure is used to limit the growth of oxides to one or less than one monolayer in order to continue the silicon epitaxial growth. The visible EL, with electrons injected through a Schottky barrier into the c-Si= O superlattice, shows a spectrum with a peak at 2 eV. The EL device has been life-tested for over seven months without degradation. The robustness and stability of the c-Si= O superlattice would open a door for combining IC with integrated optics. ? 2000 Elsevier Science B.V. All rights reserved. PACS: 78.60.F Keywords: Electroluminescence; Photoluminescene; Superlattice Since the discovery of strong visible photolumines- cence from porous silicon [1], it seemed that a process which is compatible with the silicon processing in- dustry is at hand for photonic devices [2,3]. Quantum size eects resulting in an increase in the silicon band gap have been demonstrated in terms of nanowires [1,4] and nanodots [5,6]. El devices have been built upon silicon-based nanostructures [7–10]. The best light-emitting devices (LED) reported from porous Si and other silicon nanomaterials lasted no more than several weeks under DC or continuous pulse opera- tion. For practical applications, it is essential to over- * Corresponding author. Tel. +1-704-547-3147. E-mail address: qizhang@uncc.edu (Q. Zhang) come the extreme reactivity and fragility of porous silicon. We report an extremely stable electrolumines- cence (EL) device from crystalline-Si= O superlattice, grown by molecular-beam-epitaxy (MBE) with in situ oxygen exposure. The device has been life-tested for more than seven months under continuous operation. The robustness and stability of the c-Si= O superlattice may open the door for combining IC (integrated cir- cuits) with IO (integrated optics). The concept of c-Si= O superlattice was proposed a few years ago as a barrier for silicon quantum devices [11]. Thin silicon epitaxially grown, sandwiched be- tween monolayer of adsorbed oxygen, provides a bar- rier for quantum connement. A superlattice structure consisting of Si nanocrystallites sandwiched between 1386-9477/00/$ - see front matter ? 2000 Elsevier Science B.V. All rights reserved. PII:S1386-9477(99)00261-1