Journal of Crystal Growth 237–239 (2002) 869–873 GrowthofluminescentZn 2 SiO 4 :Mn 2+ particlesinsideoxidized porous silicon: emergence of yellow luminescence N. Taghavinia a, *, G. Lerondel a , H. Makino a , A. Yamamoto b ,T.Yao a , Y. Kawazoe a , T. Goto b a Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan b Department of Physics, Tohoku University, Sendai 980-8578, Japan Abstract PoroussiliconlayerswereactivatedbytheadditionofZn 2 SiO 4 :Mn 2+ whichresultedingreenoryellowluminescent samplesdependingonthetreatmentconditions.Theyellowpeakoccursat575nmandhasaconsiderablylongerdecay time than the green peak, which occurs at 525nm. It is demonstrated that the yellow luminescence comes from small particles,typically30nminsize,whichhavebeencrystallizedinthe b-phase, while the green luminescence comes from theusual a-phase,whichoccurswithlargerparticles. b-Phaseappearstobethedominantphaseforsmallparticlesand anyconditionthatresultsintheformationofsmallparticlesgivesrisetoyellowemission. r 2002ElsevierScienceB.V. All rights reserved. PACS: 82.33.Ln; 81.07.-b; 81.40.Tv; 78.55.Mb Keywords: A1. Nanostructures; A3. Impregnation of porous materials; B1. Silicates; B2. Phosphors 1. Introduction Impregnation of porous silicon (PS) with luminescent materials has been the subject of many research works recently. The primary purpose of these works is to achieve silicon-based luminescentdevices,whichcanbecoupledwiththe already known silicon technology. Different ma- terials and methods have been tried for PS impregnation in order to find stable and high luminescence structures. Er attracted interest as an activator, because of its 1.5 mm luminescence, which is the desired wavelength for fiber optics communications [1]. Various dyes were also introduced in the pores of PS layers by simple immersion methods [2]. Semiconductor nano- crystals, such as CdSe, have also been grown into PS layers [3]. The problem, however, remains the low efficiency of the luminescence from the impregnated PS layers. This can be both due to the absorption of the emitted light by the silicon skeleton, and the low quantum efficiency of the luminescence from the activator Here we introduce a new way to impregnate PS by silicate phosphor particles, particularly Zn 2 SiO 4 :Mn 2+ . The method is based on diffusing Zn and Mn species into the pores of PS layer and high-temperature reaction of them with the silicon *Corresponding author. Tel.: +81-22-215-2074; fax: +81- 22-215-2073. E-mail address: nima@imr.tohoku.ac.jp (N. Taghavinia). 0022-0248/02/$-see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-0248(01)02041-3