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Resistive Memory Devices Based on Metal Coordinated Azo Aromatics

Technology #2016-311

Robust Resistive Memory Devices Using Solution-Processable Metal-Coordinated Azo-aromatics

Thirumalai Venkatesan*, Goswami Sreetosh, Patra Abhijeet, Goswami Sreebrata

*NUS Nanoscience and Nanotechnology Initiative (NUSNNI)

Industry Problem

Resistive memory devices offer an alternative to flash memory as non-volatile storage as well as processing devices which are ubiquitous in the forward looking digital electronics including internet of things (IoT), artificial intelligence (A.I.). Organic resistive memories can play a crucial role here owing to their cheap fabrication process along with synthetic tunability. However, devices reported till date suffer from a lack of reproducibility, stability, endurance, as well as the understanding of the device mechanisms. These difficulties are essential to be overcome to furnish a good candidate for commercial applications.


Prof Venkatesan’s team from NUSNNI, Nanocore in collaboration with Prof. Goswami’s group in Indian Association for the Cultivation of Science (IACS) has invented a novel resistive memory device based on solution-processable metal-coordinated azo-aromatics. The devices are reproducible (demonstrated over 400 devices), air stable, scalable (till) (see Fig. 3)and they show durability of more than 1012 write/read/erase/read cycles (see Fig. 4). Besides, the stability of bot50nm2h on and off states at 350K over a month along with a large On/Off ratio (> 104 between conductance states) and a fast switching speed (demonstrated till 30ns) make these devices suitable for industrial applications. In fact our devices, in 50nm2 dimension exceed each of parameters set in International Technology Roadmap for Semiconductors (ITRS-2015) which has so far been unprecedented in any organic memory device reported in the last 2 decades. NUS has filed a patent application for the invention.

Keywords: resistive memory device azo-aromatics

Fig. 1: Organic Resistive memory device schematic with the molecular film sandwiched between two electrodes.

 Fig. 2: Current density-Voltage curves of 321 devices with different top electrode sizes. 

 Fig. 3: (a) A device with c-AFM top electrode  and (b) its characteristics

 Fig. 4: (a) Demonstration of switching speed of ~30ns  (b) Endurance of 1012 cycles measured with pulse trains shown in Fig. 4a.

 Fig. 5: Stability of the device measured  over a month at 350K

Value Proposition

  • High ambient durability (more than 1012 write/erase cycles)
  • High reproducibility (0.8% spread in on/off ratio for 321 devices)
  • Large On/Off ratio (> 104 between conductance states)
  • Stability of the on and off for more than 2 months at 350K
  • Scalable down to 50 nm2
  • Switching voltage ~ 100mV for a 50nm2 device
  • Switching energy < 1fJ
  • Flexible

Other Potential Application

  • Memory devices (especially in flexible portable devices)
  • Logic circuit elements
  • Neuromorphic computing

For more information, contact:

NUS Industry Liaison Office

Case Manager: Tan Yan Ny

+65 6516 7175

Case Manager: Dr. Tan Yan Ny

ILO Ref: 2016-311 

Principal Investigator: Prof Chen Wei

PI’s contact:

Prof Thirumalai Venkatesan