Journal of Crystal Growth 305 (2007) 99–103 Shape-controlled synthesis and optical characterization of chalcopyrite CuInS 2 microstructures Shengjie Peng, Jing Liang, Li Zhang, Yunhui Shi, Jun Chen à Institute of New Energy Materials Chemistry, Nankai University, Tianjin 300071, People’s Republic of China Received 22 October 2006; received in revised form 20 January 2007; accepted 9 February 2007 Communicated by K. Nakajima Available online 1 April 2007 Abstract We described in this paper the shape-controlled synthesis of chalcopyrite CuInS 2 microspheres via a solution-based route. A facile hydro/solvothermal approach was developed to control the morphologies and microstructures of CuInS 2 by employing different solvents and sulfur sources. The measurement techniques, including X-ray powder diffraction (XRD), infrared (IR) spectrum, scanning electron microscope (SEM) and UV–vis absorption spectra were used to characterize the as-obtained products. XRD spectra revealed the presence of chalcopyrite CuInS 2 . SEM images indicated that the as-prepared CuInS 2 were microspheres, which were composed of nanoplates or nanoparticles. The UV–vis absorption spectra showed that CuInS 2 microspheres had strong absorption and their energy band gaps were tunable, which was somewhat relevant to the size and morphology of CuInS 2 . r 2007 Elsevier B.V. All rights reserved. Keywords: A1. Crystal morphology; A2. Growth from solutions; B1. Sulfides; B2. Semiconducting ternary compounds 1. Introduction The synthesis of nano- and micro-structured semicon- ductors has received intense attention for their impor- tant physical or chemical properties and their great potential applications [1–3]. During the last decade, a considerable effort has been spent in the preparation and investigation of the semiconducting family of wide-band gap II–VI multinary chalcogenide compounds ABmCn (A ¼ Cu, Ag, Zn, etc.; B ¼ Al, Ga, In; C ¼ S, Se, Te) because of their fundamental electronic and optical properties. As a particularly promising candidate for photovoltaic applications in solar cells, the ternary chalcogenide compound CuInS 2 has been extensively studied due to its high-absorption coefficient, suitable band gap, good radiation stability, and easy conversion of n/p carrier type. Up to now, different morphologies of CuInS 2 thin film and powders have been obtained, such as nanoparticles [4,5], nanorods [6,7], nanotubes [8], nanowires [9], foam- like CuInS 2 nanocrystallites [10], and porous microspheres [11]. It is noted that various techniques such as chemical vapor deposition (CVD) [12], sputtering [13], spray pyrolysis [14], molecular beam deposition [15], and electrodeposition [16] have been explored to fabricate CuInS 2 . Since the shape, size, and dimensionality of semiconductors are important parameters for their proper- ties, developing a facile method to synthesize ternary chalcogenide materials with various morphologies is of interest and importance for their further application [17]. In our previous work, we have described shape-controlled synthesis of ternary chalcogenide ZnIn 2 S 4 and CuIn(S,Se) 2 nano/microstructures in the presence of surfactants via a solution route [18,19]. Here, we report a facile one-pot hydro/solvothermal method to fabricate CuInS 2 micro- spheres without surfactants. The reaction parameters of the obtained CuInS 2 samples were also studied. In addition, the optical properties of the as-synthesized CuInS 2 microspheres were investigated, which indicated the correlation between the shape and the band gaps of the products. ARTICLE IN PRESS www.elsevier.com/locate/jcrysgro 0022-0248/$ - see front matter r 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2007.02.040 à Corresponding author. E-mail address: chenabc@nankai.edu.cn (J. Chen).