Journal of Alloys and Compounds 393 (2005) 167–170 Thickness dependent structure of -FeSi 2 grown on silicon by solid phase epitaxy N. Vouroutzis a , T.T. Zorba a , C.A. Dimitriadis a,∗ , K.M. Paraskevopoulos a , L. D ´ ozsa b , G. Moln´ ar b a DepartmentofPhysics,UniversityofThessaloniki,54124Thessaloniki,Greece b ResearchInstituteforTechnicalPhysicsandMaterialsScience,P.O.Box49,BudapestH-1525,Hungary Received 7 September 2004; received in revised form 30 September 2004; accepted 4 October 2004 Available online 28 November 2004 Abstract Semiconducting -FeSi 2 was grown on Si(0 0 1) substrates by depositing Fe layers of thickness 2, 4 and 6 nm at room temperature in an ultra-high vacuum system and subsequent in situ annealing at 600 ◦ C for 15 min. The phase of the grown polycrystalline -FeSi 2 was confirmed by electron diffraction and infrared reflectance measurements. Transmission electron microscopy analysis has shown that the structure of the formed -FeSi 2 is thickness dependent. For an Fe layer of thickness 2 nm, -FeSi 2 nanodots with a mean diameter of about 15 nm were grown, together with islands of irregular shape and linear or S-type arrays of -FeSi 2 nanodots. For thicker Fe layers, the grown -FeSi 2 consisted of continuous polycrystalline layers. © 2004 Elsevier B.V. All rights reserved. Keywords: Solid phase epitaxy; -FeSi 2 ; Nanodots; Polycrystalline layer 1. Introduction The preparation of artificial low dimensional structures for electron confinement is one of the most challenging research fields of the solid-state technology [1]. The research of the quantum dots has increased dramatically over the past few years due to the predicted drastic improvement in the performance of optoelectronic devices. Phenomena of self-assembly have been observed, besides the compound semiconductors of group IV, in a wide range of material and substrate combinations [2]. Heteroepitaxial growth of strained semiconductor structures have attracted great in- terest recently, owing to their scientific interest and possible technological importance as quantum dots [3]. The generated dots, through the combination of growth kinetics and strain effects, show a rather narrow size distribution on the substrate. The semiconducting iron disilicide (-FeSi 2 ) has attracted much attention due its potential application in silicon-based ∗ Corresponding author. E-mailaddress: cdimitri@skiathos.physics.auth.gr (C.A. Dimitriadis). optoelectronics. The band gap of -FeSi 2 is direct (about 0.87 eV at room temperature) [4], making this material a potential candidate for infrared light emitting devices or de- tectors, whereas a lot of effort has been made to prepare semi- conducting polycrystalline -FeSi 2 layers [4–7], less work has been performed to grow -FeSi 2 nanodots on Si substrate. Earlier, few publications reported island or wire-like aggregation of silicides on Si substrates. TiSi 2 islands were observed on both Si(1 0 0) and Si(1 1 1) substrates by depositing Ti layers at elevated temperatures, followed by high temperature annealing [8]. Nanostructures of CoSi 2 were prepared on Si(1 0 0) substrate by reactive deposition epitaxy (RDE) and their nucleation and evolution were studied during the annealing [9]. Formation of the rare earth Er, Dy, Ho silicide nanowires have also been reported [10,11]. Recently, -FeSi 2 islands were grown by means of Fe + implantation into Si(1 0 0), followed by thermal annealing at 800 ◦ C [12]. In this work, -FeSi 2 was grown on Si(0 0 1) substrates by solid phase epitaxy, with variable thickness of the Fe layer. The phase of the formed silicide was identified by infrared (IR) reflection measurements, 0925-8388/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2004.10.005