Microelectronic Engineering 70 (2003) 209–214 www.elsevier.com / locate / mee Transport properties of Mn-doped Ru Si 2 3 a,b, a a b b b * L. Ivanenko , A. Filonov ,V. Shaposhnikov , G. Behr , D. Souptel , J. Schumann , b b a H. Vinzelberg , A. Plotnikov ,V. Borisenko a Belarusian State University of Informatics and Electronics, P . Browka St. 6, 220013 Minsk, Belarus b Leibniz Institute for Solid State and Materials Research Dresden, PF 27 00 16, D-01171 Dresden, Germany Abstract Transport properties of Mn-doped ruthenium silicide Ru Si were studied both experimentally and theoretically. The 2 3 precipitation-free Ru Si single crystals were grown by the zone melting technique with radiation heating. The temperature 2 3 dependence of the electrical resistivity and Hall coefficients of the crystals were measured. The electrical resistivity of 1% 18 Mn-doped Ru Si was lower than that of undoped crystals. The carrier concentration in the doped samples is about 10 2 3 23 cm at room temperature. Mn-doped Ru Si has a twice higher carrier mobility compared to the undoped one. Theoretical 2 3 calculation of the charge carrier mobility is based on the effective masses which are estimated from the ab initio electronic band structure and classical scattering mechanisms.  2003 Published by Elsevier B.V. Keywords: Semiconducting ruthenium silicide; Doping with manganese; Transport properties 1. Introduction taken to prepare pure as well as B-, Ga-, Ir- and Rh-doped Ru Si ; however, their Z values were 2 3 The main goal of thermoelectric studies is to found to fall short of the theoretical estimations develop materials with a high thermoelectric figure [5–8]. Manganese has been suggested as an effective of merit. In this respect, semiconducting ruthenium dopant [9], but no further investigations of transport silicide Ru Si is one of the most promising systems. properties of Mn-doped Ru Si are available so far. 2 3 2 3 Whereas most thermoelectric materials stay below This paper is the first report of such study. We the empirically established upper limit of dimension- investigated the effects of Mn-doping on electrical less figure of merit (thermoelectric efficiency) ZT #1 properties of Ru Si single crystals grown by the 2 3 [1,2], it has been theoretically demonstrated that floating zone method. Our data clearly show that Ru Si -based systems can exceed that limit [3]. Only doping with Mn can improve the electrical properties 2 3 single crystals with a high structural perfection allow of the semiconducting ruthenium silicide. reliable assessments of the maximum power factor 2 S /r as an important contribution to the thermoelec- tric efficiency [4]. Several attempts have been under- 2. Experiments 2.1. Sample preparation *Corresponding author. Tel.: 1375-172-398-869; fax: 1375- 172-310-914. E-mail address: ivanenko@nano.bsuir.edu.by (L. Ivanenko). The Mn-doped Ru Si single crystals were grown 2 3 0167-9317 / 03 / $ – see front matter  2003 Published by Elsevier B.V. doi:10.1016 / S0167-9317(03)00424-6