Microstructure and nanohardness of the diluted magnetic semiconducting Cd 1x Mn x S nano-crystalline films D. Sreekantha Reddy a, * , B.K. Reddy a , N. Koteeswara Reddy b , K.R. Gunasekhar c , P. Sreedhara Reddy a a Department of Physics, Sri Venkateswara University, Tirupati 17502, India b School of Chemical Engineering and Technology, Chonbuk National University, Jeonju 561756, South Korea c Department of Instrumentation, Indian Institute of Science, Bangalore 60012, India Received 29 January 2007; received in revised form 8 March 2007; accepted 8 March 2007 Available online 23 March 2007 Abstract Cd 1x Mn x S nano-crystalline films (0  x  0.5) were formed on glass substrates by thermal evaporation technique at room temperature (300 K). AFM studies showed that all the films were in nano-crystalline form with the grain size varying in the range between 36 and 58 nm and exhibited hexagonal structure of the host material. The lattice parameters varied linearly with composition, following Vegard’s law in the entire composition range. The nanohardness and Young’s modulus decreased sharply with ‘Mn’ content upto x = 0.3 and increased with high Mn content. # 2007 Elsevier B.V. All rights reserved. PACS : 62.25.+g; 68.47.Fg; 61.72.Vv; 62.20.x; 68.35.Gy; 68.37.Ps Keywords: Diluted magnetic semiconductors; Cd 1x Mn x S nano-crystalline films; Microstructure; Nanohardness and Young’s modulus 1. Introduction Diluted magnetic semiconductors (DMS) ingeniously utilizes carrier charge and spin degrees of freedom. DMS are non- magnetic semiconductors in which a fraction of host cations are replaced by magnetic ions in which new function can be added by transporting and controlling various types of spin states [1,2]. Diluted magnetic semiconductors are considered as ideal systems for spintronics. Among the various kinds of DMSs, of the A 1X II Mn X B VI type have attracted considerable attention due to the following reasons. First, the concentration of charge and spin can be controlled independently by changing the concentrations of dopant elements injecting carriers and Mn ions. Secondly, it may promise new functionality such as spin- valve transistors and non-volatile storage. One of the reasons for these controversial results seems to come from either the quality or the reproducibility of the sample, which might change the physical and chemical properties of the sample. A new challenge in modern microelectronics is to manipulate both the spin and the charge of the electron, which would add a new degree of freedom in electronic devices. Doping in semiconductors with selective elements can offer an effective method to adjust their electrical, optical and magnetic properties. ‘Mn’ doping severely sup- presses the luminescence of Cd 1x Mn x S even at a very low doping level. Diluted magnetic semiconductor is expected to play an important role in interdisciplinary materials science and future electronics because charge and spin degrees of freedom accommodated into single matter resulting in interesting magnetic, magneto-optical, magneto electronic and other properties [3–14]. During the few decades, the synthesis and characterization of diluted magnetic semiconductors (DMS) have been extensively studied due to their wide range of DMS applications. This is mainly because DMS have very attractive physical and mechanical properties. Mn based II–VI alloys have found increasing commercial applications due to their enabling properties such as hardness, Young’s modulus and corrosion resistance, magnetic properties and electrical proper- ties. The applications range from hard and protective coatings on mechanical tools to decorative coatings and to diffusion www.elsevier.com/locate/apsusc Applied Surface Science 253 (2007) 7318–7322 * Corresponding author. Tel.: +91 9440313110. E-mail address: dsreddy_physics@rediffmail.com (D.S. Reddy). 0169-4332/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2007.03.025