Understanding the electronic properties of single- and double-stranded DNA
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THE EUROPEAN PHYSICAL JOURNAL E
Regular Article
Understanding the electronic properties of single- and double-stranded DNA Souhad M.A. Daraghma, Sara Talebi, and Vengadesh Periasamya Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia Received 10 October 2019 and Received in final form 26 May 2020 Published online: 19 June 2020 c EDP Sciences / Societ` a Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2020 Abstract. Understanding the charge transfer mechanism through deoxyribonucleic acid (DNA) molecules remains a challenge for numerous theoretical and experimental studies in order to be utilized in nanoelectronic devices. Various methods have attempted to investigate the conductivity of double-stranded (ds-) and single-stranded DNA (ssDNA) molecules. However, different electronic behaviors of these molecules are not clearly understood due to the complexity and lack of accuracy of the methods applied in these studies. In this work however, we demonstrated an electronic method to study the electrical behavior of synthetic ssDNA or dsDNA integrated within printed circuit board (PCB)-based metal (gold)-semiconductor (DNA) Schottky junctions. The results obtained in this work are in agreement with other studies reporting dsDNA as having higher conductivity than ssDNA as observed by us in the range of 4–6 μA for the former and 2–3 μA for the latter at an applied bias of 3 V. Selected solid-state parameters such as turn-on voltage, series resistance, shunt resistance, ideality factor, and saturation current were also calculated for the specifically designed ss- and dsDNA sequences using the thermionic emission model. The results also showed that the highest conductance was observed for dsDNA with guanine and cytosine base pairs, while the lowest conductance was for ssDNA with adenine and thymine bases. We believe the results of this preliminary work involving the gold-DNA Schottky junction may allow the interrogation of DNA charge transfer mechanisms and contribute to better understanding its elusive electronic properties.
1 Introduction DNA is the basic building block of life. It has a doublehelix structure, consisting of four complementary bases; adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C). These base pairs are connected to each other by means of hydrogen bonding [1]. The helical structure of DNA is stabilized by the hydrogen bonds connecting each base with its complimentary base, and also by its hydrophobic effect and π-π stacking interaction of the base pairs [2]. Double-stranded DNA with hybridization of πz orbital, vertical to the stacked base pairs plane may lead to the conductive behavior as was suggested by Eley and Spivey in 1962 [3]. This is a very interesting feature that can be utilized in nanotechnology for building electronic devices [4,5]. Therefore, numerous studies were carried out to understand DNA charge transfer mechanism which in general is still no
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