Programmable nonvolatile memory based on gold nanoparticles in poly-methyl-silsesquioxane sol–gel Zubair Ahmad a,⇑ , P.C. Ooi b , K. Sulaiman a , K.C. Aw b , M.H. Sayyad c a Low Dimensional Materials Research Centre (LDMRC), Faculty of Science, Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia b Department of Mechanical Engineering, University of Auckland, 20 Symonds Street Auckland, New Zealand c Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi 23640, Swabi, Pakistan article info Article history: Received 3 February 2012 Received in revised form 4 June 2012 Accepted 18 July 2012 Available online 27 July 2012 Keywords: Hybrid Poly-methyl-silsesquioxane Gold nanoparticles Non-volatile memory abstract An organic–inorganic (hybrid) nanocomposite layer as non-volatile memory (NVM) using sol–gel poly- methylsilsesquioxane (PMSSQ) embedded with gold (Au) nanoparticles has been presented in this article. The NVM is based on a capacitor structure. The Au nanoparticles used in this work were synthesized by chemical reduction method whereas the PMSSQ sol–gel was prepared by using trimethoxymethylsilane (CH 3 Si(OCH 3 ) 3 ), n-BuOH and de-ionized water. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the device have been performed. The aim was to enhance the charge storage capability of the previously studied [1–3] PMSSQ nanocomposite layer based non-volatile memory (NVM), which has been successfully increased up to 100%. The NVM is based on a capacitor structure. The memory cell showed good programmed/erased characteristics. Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Organic materials provide a diversity of interesting electronic properties, making the realization of organic electronics devices with advantages over the conventional inorganic technology [1,2,4]. Non-volatile memory (NVM) devices based on conventional silicon technology have been used in various applications ranging from computer memory to portable flash drives. However, for large area low-cost electronics such as system on panel, there is need to development of cost-effective memory devices and solution pro- cessing technique will be very attractive. The emerging field of or- ganic electronics has the potential for NVM applications due to their key advantages of simple and low-temperature thin-film pro- cessing through inexpensive techniques such as spin coating, ink- jet printing, or stamping [5,6]. In Refs. [5–8], researchers have re- ported that metal nanoparticles embedded in an organic blend sandwiched between two electrodes, exhibited promising perfor- mances and potential for NVM application. Organic or polymer based memories also have many other advantages over inorganic memories such as mechanical flexibility, high device density due to the possibility of stacking these devices, etc. [9,10]. Organic–inorganic (hybrid) materials present a new class of materials that may combine desirable physical properties charac- teristic of both organic and inorganic materials. The material dis- cussed in this paper, poly-methyl-silsesquioxane (PMSSQ), is a hybrid material and has excellent thermal, mechanical, electronic, and optical properties, and has potential for electronics applica- tions [9]. It has a chemical formula of CH 3 –SiO 3/2 and can occur either as ladder or cage structure. The PMSSQ is solution process- able, and has adjustable viscosity to suit various thin film solution deposition techniques i.e. stamping, spin coating, flexography, and inkjet printing, etc. The PMSSQ layer can be fully cross-linked ther- mally at a temperature that is compatible with plastic substrates for fabrication of flexible integrated circuits [9]. Memory devices embedded with metal nanoparticles have been considered more advantageous in many aspects as compared to semiconductor nanoparticles-based memories [11–13]. High work function metal nanoparticles can enhance the data retention characteristics and lower the operating voltages. Keeping in view all the above men- tioned facts, in this article, we will describe the fabrication of a NVM using a nanocomposite layer consisting of PMSSQ and gold (Au) nanoparticles. Au nanoparticles are selected for this study due to their higher work function and more chemical stability as compared to other metallic nanoparticles [14]. The aim was to enhanced the charge storage capability of the previously studied [1–3] PMSSQ nanocomposite layer based non-volatile memory (NVM), which has been successfully attained. 2. Experimental Au nanoparticles were prepared by chemical reduction [15] of an aqueous HAuCl 4 3H 2 O solution with an aqueous HOC(COO- Na)(CH 2 COONa) 2 2H 2 O. One millimolar (1 mM) aqueous solution 0167-9317/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.mee.2012.07.106 ⇑ Corresponding author. Tel.: +60 16 9582584; fax: +60 37 9674146. E-mail address: zubairtarar@gmail.com (Z. Ahmad). Microelectronic Engineering 99 (2012) 62–66 Contents lists available at SciVerse ScienceDirect Microelectronic Engineering journal homepage: www.elsevier.com/locate/mee