Contents lists available at ScienceDirect Superlattices and Microstructures journal homepage: www.elsevier.com/locate/superlattices ZnO nanorod based highly selective visible blind ultra-violet photodetector and highly sensitive NO 2 gas sensor S.K. Shaikh a , V.V. Ganbavale b , S.V. Mohite a , U.M. Patil c , K.Y. Rajpure a,* a Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur, 416004, India b Department of Physics, Dattajirao Kadam Arts, Science and Commerce College, Ichalkaranji, India c DST-INSPIRE Faculty, D.Y. Patil University, Kolhapur, India ARTICLE INFO Keywords: ZnO nanorod Chemical method MSM UV photodetector NO 2 sensor Photoresponse Sensitivity ABSTRACT By using 1D ZnO nanorod, obtained from a simple two step chemical method as the sensor material, we report the fabrication of highly selective metal-semiconductor-metal (MSM) ultra- violet (UV) photodetector and NO 2 gas sensor. The fabricated MSM UV photodetector and gas sensor possesses simplicity in material synthesis and sensor design. The effect of morphological evolution and structural intactness on the sensing properties of UV photodetector and NO 2 gas sensor are deeply studied. The well aligned 1 dimensional (1D) ZnO nanorod provides high surface area for the sensing mechanism. The UV photodetector possesses high responsivity in the UV A region (364.81 A/W) with fast photoswitching characteristics at 5 V bias. It shows for- mation of good ohmic contact between metal semiconductor junctions. NO 2 sensing measure- ment was carried out at relatively lower temperature of about 175 °C. The ZnO nanorods are highly selectivity towards NO 2 gas and maximum gas response observed is 35 at 40 ppm of NO 2 . The NO 2 gas sensor shows good repeatability at lower gas concentration of 2 ppm. The present synthesis technique provides cost effective route for obtaining highly ordered ZnO nanorods with simple sensor technology for multifunctional ZnO nanorod sensor. 1. Introduction Multifunctional uses of semiconductor devices have attracted great attention of researchers due to their use in various optoe- lectronic devices. These devices are also known as multifunctional or smart devices. Recently, 1D semiconductor nanostructures are used as promising materials because of their eye catching chemical and physical properties; these nanostructures also have tre- mendous potential to expose multifunctional application in single nanostructure. Nowadays varieties of gas sensors are available for the detection of various pollutants present in the atmosphere. Among many pollutants nitrogen dioxide is important air pollutant. Nitrogen dioxide is one of the primary sources of acid rain and it is important air pollutant which is generated by combustion facilities and automobiles. The detection of NO 2 is important because it has hazardous effects on the human bodies like breathing, etching and asthma. Hence there is strong need to develop NO 2 gas sensors with high sensitivity at lower operating temperature, low cost and with lower power consumption. Many metal oxides are studied for the fabrication of NO 2 gas sensor viz. SnO 2 , graphene, and MoO 3 etc. [1–3]. As like NO 2 gas detection, UV monitoring in the environment is also has great importance. Solar ultraviolet A i.e. UV A (320–400 nm) are hazardous to human health, it attacks on deeper skin layers due to which tissue and blood vessel are affected. On the other hand UV radiations are also used for the degradation of the harmful organic dies present in the drinking water [4]. Many https://doi.org/10.1016/j.spmi.2018.05.021 * Corresponding author. E-mail address: rajpure@yahoo.com (K.Y. Rajpure). Superlattices and Microstructures 120 (2018) 170–186 Available online 14 May 2018 0749-6036/ © 2018 Elsevier Ltd. All rights reserved. T