Multibit Optoelectronic Memory
September 21, 2018 | NUSEstimated reading time: 2 minutes
NUS scientists have developed multibit optoelectronic memory using a heterostructure made of two-dimensional (2D) materials for next generation devices.
Optoelectronic memories are devices which can store photon-generated charge carriers when exposed to light. The stored charges can be accessed later for information retrieval. These devices can be used in image capture and spectrum analysis systems. 2D atomically layered materials are promising candidates for the development of next generation optoelectronic memories to meet emerging requirements for device miniaturisation and structural flexibility. However, optoelectronic memories fabricated using 2D materials have been reported to suffer from poor data storage capability with the highest reported figure at about eight distinct storage states.
A team lead by Prof CHEN Wei from both the Department of Chemistry and the Department of Physics, NUS has developed a multibit, non-volatile optoelectronic memory device that is able to store up to 130 distinct states by using a tungsten diselenide/ boron nitride (WSe2/ BN) heterostructure. The heterostructure, made of 2D materials, comprises a monolayer of WSe2 on a 20-layer BN. The programming (store data) and erasing (delete data) functions are controlled by adjusting the applied polarity to the device. A negative polarity is applied during the programming function and it causes the photon-generated electrons from the midgap donor-like states of the BN material to transfer into the WSe2 material. This leaves behind localised (non-mobile) positive charges in the BN material. For the erasing function, a positive polarity is applied. This causes the photon-generated electrons from the valence band in the BN material to recombine with the localised positive charges, returning it to a neutral state.
The amount of electrons transferred into the WSe2 material is dependent on the duration of light exposure time for the device. A longer exposure time would mean that more electrons are transferred. The researchers found that the continual accumulation of electrons in the WSe2 material corresponding up to 130 light pulses can be detected before saturation conditions set in. Each of these pulses can be treated as a distinct storage state. During performance testing, they found that the device exhibits a data retention of over 4.5×104 seconds and a cyclic programme/ erase endurance exceeding 200 cycles.
Explaining the significance of the findings, Prof Chen said, “Although there is still a performance gap when compared to commercial silicon-based memory, these devices are advantageous in electronic applications which require structural flexibility. The use of this WSe2/ BN 2D layered heterostructure provides a method to achieve multibit memory device and may pave the way for the development of next generation optoelectronic memories.”
Suggested Items
Groundbreaking Ceremony Marks the Beginning of a New Era for Newccess Industrial; The Construction of the MINGXIN Building
04/12/2024 | Newccess IndustrialOn a clear and sunny day in March, the groundbreaking ceremony for the MINGXIN Building took place in Shenzhen, China. This moment marked the official commencement of construction for a project that will reshape the semiconductor materials industry.
The Need for a Holistic Global Sustainability Standard
04/10/2024 | Michael Ford, Aegis SoftwareNo one can deny that the resources of our fragile planet are finite. The environment seems like a third party, subject to constant degradation. We’re acutely aware of the effects of pollution on our climate, and despite our “throw-away” culture, recycling and recovery of materials has remained relatively expensive, even as we use more energy just to survive.
iNEMI Publishes Four Roadmap Topics
04/04/2024 | iNEMIThe International Electronics Manufacturing Initiative (iNEMI) announces the availability of the first roadmap topics in the new iNEMI Roadmap format. Printed circuit boards, sustainable electronics, smart manufacturing, and mmWave materials and test are now available online.
Insulectro’s 'Storekeepers' Extend Their Welcome to Technology Village at IPC APEX EXPO
04/03/2024 | InsulectroInsulectro, the largest distributor of materials for use in the manufacture of PCBs and printed electronics, welcomes attendees to its TECHNOLOGY VILLAGE during this year’s IPC APEX EXPO at the Anaheim Convention Center, April 9-11, 2024.
Checking In With ICAPE Group
04/03/2024 | Nolan Johnson, I-Connect007ICAPE Group’s field application engineer Erik Pederson drills down on sustainability, supply chain resiliency, and what value engineering really looks like in this exclusive interview. Founded in 1999, European-based ICAPE Group provides 21 million printed circuit boards and over six million technical parts to manufacturers every month. With 30 PCB manufacturing partners globally and 50 partners providing a wide array of technical parts, ICAPE Group has operations in China, Taiwan, Thailand, South Korea, Vietnam, South Africa, Europe, Mexico, and the United States. The company also focuses on the value proposition for its customers.