Electrical and interface characteristics of nanocrystalline n-Zn 0.5 Cd 0.5 S/p-Cu 2 S heterojunction structure prepared by dip coating A.A.M. Farag a,⇑ , M. Abdel Rafea b , Sara Gad b , N. Roushdy b a Thin Film Laboratory, Physics Department, Faculty of Education, Ain Shams University, Heliopolis, Roxy, Cairo 11757, Egypt b Electronic Materials Department, Advanced Technology and New Materials Institute, City for Scientific Research and Technology Applications, P.O. 21934 New Borg El Arab City, Alexandria, Egypt article info Article history: Received 18 February 2012 Received in revised form 19 April 2012 Accepted 29 April 2012 Available online 5 May 2012 Keywords: Nanostructures Thin films Dip coating Electrical properties abstract Nanocrystalline of n-Zn 0.5 Cd 0.5 S/p-Cu 2 S heterojunctions were suc- cessfully prepared by the dip coating method. The surface morphol- ogy and the composition analysis were made by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) technique, respectively. Temperature dependent current–voltage characteris- tics of the heterojunctions were measured in the temperature range 300–400 K with a step of 25 K. The current–voltage (I–V) character- istics exhibit electrical rectification behavior. The zero bias barrier height (U B0 ) and the ideality factor (n) are affected by temperature. Interface states at the n-Zn 0.5 Cd 0.5 S/p-Cu 2 S heterojunction play a crucial role in determining the electrical characteristics of the het- erojunction. The high value of n can be ascribed to the presence of an interfacial layer. The energy distribution profile of the density of interface states (N ss ) was extracted from the forward bias I–V mea- surements using the width of the depletion region deduced from the capacitance -voltage characteristics at high frequency (1MHz). Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Nanocrystals of II–VI semiconducting materials have been previously investigated as promising in a number of application areas including biological markers [1,2], light-emitting diodes [3], solar cells [4], and color-converted solid-state lighting devices [5]. 0749-6036/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.spmi.2012.04.021 ⇑ Corresponding author. Tel.: +20 33518705; fax: +20 22581243. E-mail address: alaafaragg@yahoo.com (A.A.M. Farag). Superlattices and Microstructures 52 (2012) 288–298 Contents lists available at SciVerse ScienceDirect Superlattices and Microstructures journal homepage: www.elsevier.com/locate/superlattices