Materials Science and Engineering B81 (2001) 67 – 70 Uniformly and selectively doped silicon:erbium structures produced by the sublimation MBE method M. Stepikhova a, *, B. Andreev a , Z. Krasil’nik a , A. Soldatkin a , V. Kuznetsov b , O. Gusev c a Institute for Physics of Microstructures, Russian Academy of Sciences, 603600 Nizhnii Nogorod GSP-105, Russia b Nizhnii Nogorod State Uniersity, Gagarin Ae. 23, 603600 Nizhnii Nogorod GSP-105, Russia c A.F. Ioffe Physico -Technical Institute RAS, St.-Petersburg 194021, Russia Abstract Si:Er structures produced by an original sublimation MBE method demonstrate intense Er-related luminescence at 1.54 m both ‘as grown’ and after annealing procedure. In this contribution we discuss the peculiarities of formation of optically active Er centers in these materials and their transformation behavior depending on the growth and annealing conditions. The photoluminescence features of uniformly Er-doped layers and of the specific selectively doped structures consisting of many periods of Si and Si:Er layers with the thicknesses down to 20 A  are described. A remarkable high luminescence efficiency of the selectively doped multi-layer structures as compared to the uniformly doped is pointed out. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Sublimation MBE; Erbium; Photoluminescence; Er centers www.elsevier.com/locate/mseb 1. Introduction In the last decade unabated interest has been devoted to Er-doped silicon. This material is considered as one of the most promising for optoelectronic applications, particularly for fiber-optics communication systems. Recently Er-doped Si light-emitting diodes have been successfully prepared by means of ion implantation [1] and molecular beam epitaxy (MBE) [2] techniques. In this paper we report on the application of original sublimation MBE method (SMBE) for the growth of high effective light-emitting Si:Er structures. Two type of structures are a subject of interest, namely: (i) the uniformly doped Si:Er layers and (ii) the selectively doped structures produced by a special way in SMBE growth method and consisting of many periods of Si and Si:Er layers with the thicknesses down to 20 A  . We describe here the photoluminescence (PL) features and compare the luminescence efficiencies of these struc- tures depending on the growth and postgrowth anneal- ing conditions, as well as discuss the origin and formation processes of the optically active Er centers dominating in these materials. 2. Experimental Sublimation MBE method was developed for the growth of Er-doped light-emitting structures recently [3] and represents a modification of MBE technique where the fluxes of Si and doping impurities are pro- duced by the sublimation of appropriate current-heated sources. Polycrystalline Si plates intentionally doped with Er and the pure monocrystalline Si wafers were applied in our case to grow uniformly and selectively doped structures. The structures were grown on p- and n-type Si (100) substrates at temperatures of 400 – 700°C and are characterized by the following parameters-uniformly doped Si:Er layers: the thickness- 0.2 4 m, Er concentration-(0.5 5)·10 18 cm -3 ,O concentration-(1 10)·10 19 cm -3 (obtained from SIMS measurements)-selectiely doped multi -layer Si /Si:Er / Si /Si:Er / … structures: the thickness of Si:Er layers- 20 500 A  , the thickness of Si intermediate * Corresponding author. Tel.: +7-831-2675037; fax: +7-831- 2675553. E-mail address: mst@ipm.sci-nnov.ru (M. Stepikhova). 0921-5107/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0921-5107(00)00729-7