Herein, we report the first observation of Negative differential resistance (NDR) associated with resistance switching in Vanadyl-phthalocyanine (VOPc) based devices with the configuration: ITO/F4TCNQ/VOPc/MoO3/Al. It was observed that the devices were initially at low resistance ON state (LS) and were switched to high resistance OFF state (HS) at sufficient applied bias. The NDR behaviour was observed during the initial sweep for each device (often referred to as the writing process). The ON/OFF state transition was attributed to the formation and neutralization of interface dipoles at the ITO/VOPc interface. Finally, the observed non-volatile RS switching behaviour was demonstrated employing impedance spectroscopic studies. This study opens up the potential applications of VOPc Resistance Switching devices in security and data protection applications. © 2020 Elsevier B.V.

Kiran M.R.

Ulla H.

Krishnamanohara

Satyanarayan M.N.

Umesh G.

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

Synthetic Metals

In this paper, the dc electrical properties of Vanadyl phthalocyanine (VOPc) thin films were explored in a hole-only device configuration: ITO/MoO3/VOPc/MoO3/Al. The fabricated diode device was investigated using current density-voltage (J-V) characteristics by varying the substrate temperature from 303 K to 373 K with an interval of 5 K. The barrier height at the ITO/VOPc interface was observed to be reduced from 500 meV to 428 meV as temperature increases. The electrical conduction mechanism was found to be space charge limited currents with exponential trap distribution. Further, the hole-mobility was realized to increase from 1.7 × 10−7 cm2V−1s−1 to 1.2 × 10−5 cm2V−1s−1 (2 orders) with a rise in temperature from 303 K to 373 K. The effective trap density in our device was estimated as Nt ~5.5 × 1022 m−3. However, the improved hole-mobility with temperature is attributed to the enhanced injection of charge carriers (thermally generated) along with the reduction of barrier height. © 2021 Elsevier B.V.

Physica B: Condensed Matter

Exploring the temperature-dependent hole-transport in vanadyl-phthalocyanine thin films

Optical Materials

Optoelectronic properties of hybrid diodes based on vanadyl- phthalocyanine and zinc oxide nanorods thin films

ACS Omega

Nonvolatile Memory Device Based on Copper Polyphthalocyanine Thin Films

Journal of Electronic Materials

Resistive Switching and Nonvolatile Memory in TiO2/CuPc Nanocomposite Devices

Chemical Society Reviews

Organic and hybrid resistive switching materials and devices

RSC Advances

Metal phthalocyanine organic thin-film transistors: changes in electrical performance and stability in response to temperature and environment

Observation of resistance switching in Vanadyl-phthalocyanine thin films