Structural and optical characterisation of CdSe 1  y S y J. Díaz-Reyes a,n , J.I. Contreras-Rascón b , J.S. Arias-Cerón c , J.F. Sánchez-Ramírez a , M. Galván-Arellano c , J. Martínez-Juárez d , J.A. Balderas-López e a Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Ex–Hacienda de San Juan Molino. Km. 1.5. Tepetitla, Tlaxcala 90700, México b Universidad del Valle de Puebla, 3 Sur No. 5759. Col. El Cerrito. Puebla, Puebla 72440, México c Departamento de Ingeniería Eléctrica, SEES, CINVESTAV-IPN, Apartado Postal 14-740. México, D. F. 07000, México d Centro de Investigación en Dispositivos Semiconductores, Benemérita Universidad Autónoma de Puebla, 14 Sur y Av. San Claudio Edif. 103C, Ciudad Universitaria, Col. San Manuel, Puebla, Puebla 72570, México e Unidad Profesional Interdisciplinaria de Biotecnología del Instituto Politécnico Nacional, Avenida Acueducto S/N, Col. Barrio la Laguna, Ticomán, México, D.F. 07340, México article info Keywords: CdSe 1y S y X-ray diffraction HRTEM Raman spectroscopy Optical band gap Photoluminescence abstract In this work presents the structural and optical characterisation of cadmium selenide sulphur (CdSe 1y S y ) deposited by chemical bath deposition (CBD) technique at a deposited temperature of 20 72 1C varying the sulphur molar fraction from 0% to 42.13%, which is realized by varying the thiourea volume added to the growth solution in the range from 0 to 30 ml. The CdSe 1y S y chemical stoichiometry was determined by energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) analysis and Raman spectroscopy reveal that CdSe 1y S y deposited nanofilms showed hexagonal wurtzite crystalline phase. The average grain size range of the films was from 1.48–9.2 nm that was determined using the Scherrer– Debye equation from W(200) crystalline direction, which was confirmed by high resolution transmission electron microscopy (HRTEM). CdSe 1y S y band gap energy can be varied from 1.86 to 2.15 eV by varying the sulphur molar fraction incorporated in the nanofilms. The room temperature photoluminescence presents a dominant band about 3.0 eV that may be associated with the grain size of the nanoparticles. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction The cadmium chalcogenide CdSe 1y S y semiconducting alloy is characterised by a variable direct band gap which can be tuned by alloying, from 1.72 eV for CdSe to 2.44 eV f or CdS at room temperature. Because of excellent properties Cd(S,Se) is used in optoelectronic devices, photoconductors, gamma ray detectors, visible-light emitting diodes, lasers and solar cells ([1]; and references cited therein). CdSe 1y S y solid solutions have attracted great interest in recent years from both experimental and theoretical points of view [1, 2]. It is known that CdS and CdSe occur at normal conditions both in the wurtzite and metastable zincblende structures. [2,3]. Depending on the growth conditions, the CdSe (CdS) can be synthesised in the B4, or in the metastable B3-type structure either by molecular beam epitaxy, or by control- ling the growth temperature [4]. The equilibrium zincblende structure is observed in CdS nanostructures [5]. Under high pressure, both B3 and B4 structures convert to the denser rocksalt structure phase [2,6]. Depending on growth condi- tions using phase diagrams of the alloy CdSe 1y S y three different crystalline structure are identified: wurtzite (B4), zincblende (B3) and rock salt (B1). Ab initio calculations of Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/mssp Materials Science in Semiconductor Processing http://dx.doi.org/10.1016/j.mssp.2015.03.001 1369-8001/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author. E-mail address: joel_diaz_reyes@hotmail.com (J. Díaz-Reyes). Materials Science in Semiconductor Processing ] (]]]]) ]]]–]]] Please cite this article as: J. Díaz-Reyes, et al., Materials Science in Semiconductor Processing (2015), http://dx.doi.org/ 10.1016/j.mssp.2015.03.001i