A team led by Professor Aimin Song of the School of Electrical and Electronic Engineering has published an article in this months Nature Communications on very high speed Schottky diodes made of flexible, transparent semiconductor on plastic films. This is potentially a key discovery in the development of thin-film electronics, such as the much anticipated flexible mobile phone.
While there are hints that Samsung and LG are developing flexible phones that can fold, roll up, and even be stretched into larger screens, there are still many obstacles to overcome before bendable phones become a reality. One of the largest obstacles is the need for a high-speed flexible diode, which is what detects and modulates the cell phone’s signal. The diode must operate at high speeds in order to match the transmission frequencies (ranging from 935 MHz to 5 GHz) used by wireless cellular communication, Bluetooth, Wi-Fi, and GPS signals.
In this work, the team is able to develop a flexible Schottky diode that achieves a speed of 6.3 GHz, which makes the device the fastest of its kind to date. It is also the first flexible diode to reach what is widely considered the “benchmark speed” of 2.45 GHz, which covers the principal frequency bands used in most current wireless communications. The diodes are based on a novel flexible semiconductor film called indium-gallium-zinc-oxide (IGZO), which can be deposited at room temperature by sputtering on almost all types of substrates.
More information: Jiawei Zhang, et al. “Flexible indium-gallium-zinc-oxide Schottky diode operating beyond 2.45 GHz.” Nature Communications, 6: 7561, July 2015. DOI: 10.1038/ncomms8561
Read the publication in Nature Communications
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