Foundation Laid for Next-Generation Ultra-Miniature Electronic and Optoelectronic Devices
Nano-Schottky Diode Achieves Exceptional Current Rectification and Photoresponse
Breakthrough Enables Precise Control at the Atomic Scale for Future Nano Technologies
A Korean research team has successfully developed an ultra-miniature nano diode, measuring just one ten-thousandth the thickness of a human hair, and achieved both outstanding current rectification characteristics and photoresponse performance. This research is expected to serve as a significant breakthrough for the development of next-generation nano electronic devices and optoelectronic components.
The research team led by Professor Jihee Kim from the Department of Physics at Pusan National University (President: Choi Jaewon), in collaboration with Sungkyunkwan University and Inha University, announced on September 5 that they had implemented a nano-Schottky diode with a contact area of just 6.82 nm² by utilizing a conductive atomic force microscopy (CAFM) probe.
The Schottky diode is a key component that allows current to flow in only one direction at the interface between a metal and a semiconductor. However, as the contact area becomes smaller, issues such as current distortion or loss of desired characteristics arise, posing a fundamental limit to miniaturization.
The research team succeeded in precisely controlling current even in much narrower spaces than conventional diodes by directly contacting a CAFM probe onto a two-dimensional molybdenum disulfide (MoS₂) semiconductor placed on an ultra-flat gold electrode. Through a systematic analysis of current-voltage characteristics depending on the thickness of MoS₂, they confirmed a significantly higher rectification ratio compared to conventional large-area contact diodes. This was possible because the depletion region was extremely reduced, allowing for fine-tuned control of current flow.
This nano diode can not only control current but also function as a photodiode that detects light. The team analyzed short-circuit current, open-circuit voltage, and photocarrier transport behaviors according to the thickness of MoS₂, the wavelength of light, and the irradiation position, demonstrating that the photoelectric effect is clearly manifested even at ultra-small contact areas. This shows that a sufficient internal potential barrier can be formed even in nano-scale structures.
Sejin Oh, a combined master's and doctoral student at Sungkyunkwan University (first author), stated, "Through this research, we have demonstrated the precise control of charge flow and photoresponse at the nanometer scale, and presented the potential for new architecture designs for ultra-high-density memory devices, AR/VR, and next-generation image sensors for autonomous driving."
Professor Jihee Kim of Pusan National University (corresponding author) explained, "Contrary to the conventional belief that current control becomes difficult when the contact area is reduced to just a few nanometers, we have actually achieved higher sensitivity and rectification characteristics." She added, "We have established a new technological foundation for measuring and controlling the physical performance of electronic devices at the atomic level." She emphasized, "This research will serve as an important stepping stone for the development of various next-generation application technologies, including nano communication devices, health monitoring systems, AI-based ultra-miniature image sensors, and neuromorphic device design."
The results of this research were published in the August 14 issue of "Small," a prestigious journal in the field of materials science.
The research was supported by the Mid-Career Researcher Program and the Global Research Center (IRC) project of the National Research Foundation of Korea (NRF) under the Ministry of Science and ICT.
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