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Australian research helping self-driving cars get on the road

Researchers from the Australian National University and TMOS, an Australian Research Council Centre of Excellence, have developed a highly sensitive self-powered single photon detector that could be used to make self-driving cars safer and more energy efficient.

A fast, single-photon Light Detection And Ranging (LIDAR) is far more sensitive than other forms of LIDARs, allowing information be to be perceived earlier, and in far more detail, especially in low light or poor visibility conditions. By detecting signals earlier, the AI technology in the driver’s seat has more time to make the decisions necessary to prevent an accident. Many previous accidents involving self-driving cars have been a result of the car not being able to identify unexpected objects in a timely manner, such as pedestrians and bicycles.

Until now, single photon detectors have required an external power source or cryogenic cooling, adding to the bulk and weight of the sensor and limiting its applications. These larger, heavier sensors consume more energy, increasing costs and emissions.

In research published in Advanced Materials, the team at TMOS have demonstrated how III-V compound semiconductor nanowires have shown tremendous potential for developing high-speed single photon level detection due to their unique electrical and optical properties, as well as flexibility of device design.

Practical applications extend beyond autonomous vehicles. Even Apple’s iPhone now implement LIDAR technology.

Co-lead author on the research, from TMOS, Yi Zhu says, “The future applications of this new device could be almost limitless. We’ll see it used in space exploration, medical diagnostics, and quantum computing.”

While the technology is still in early stages, the team is confident that it maps out a pathway towards low-cost, high sensitivity, self-powered photodetectors.

Co-lead author, Vidur Raj also from TMOS, says, “the next step to seeing this technology realized is to optimize the device design to further improve its speed. That’s where our focus for 2022 will be.”

Lead researcher of the project, Professor Lan Fu says, “In the long term, we will leverage our broad research expertise on compound semiconductor nanowire materals and devices to design new detector structures such as single photon avalanche photodiodes and develop chip-scale, multi-pixel imaging arrays.”

For more information about the research, please contact connect@tmos.org.au

Self-Powered InP Nanowire Photodetector for Single-Photon Level Detection at Room Temperature

Yi Zhu, Vidur Raj, Ziyuan Li, Hark Hoe Tan, Chennupati Jagadish, Lan Fu
Highly sensitive photodetectors with single-photon level detection are one of the key components to a range of emerging technologies, in particular the ever-growing field of optical communication, remote sensing, and quantum computing. Currently, most of the single-photon detection technologies require external biasing at high voltages and/or cooling to low temperatures, posing great limitations for wider applications. Here, InP nanowire array photodetectors that can achieve single-photon level light detection at room temperature without an external bias are demonstrated. Top-down etched, heavily doped p-type InP nanowires and n-type aluminium-doped zinc oxide (AZO)/zinc oxide (ZnO) carrier-selective contact are used to form a radial p–n junction with a built-in electric field exceeding 3 × 105 V cm−1 at 0 V. The device exhibits broadband light sensitivity and can distinguish a single photon per pulse from the dark noise at 0 V, enabled by its design to realize near-ideal broadband absorption, extremely low dark current, and highly efficient charge carrier separation. Meanwhile, the bandwidth of the device reaches above 600 MHz with a timing jitter of 538 ps. The proposed device design provides a new pathway toward low-cost, high-sensitivity, self-powered photodetectors for numerous future applications.

About the author/s

Samara Thorn

As the Engagement Manager at TMOS, the ARC Centre of Excellence for Transformative Meta-Optical Systems, my role is to help researchers communicate their science and help businesses understand how the new field of meta-optics will transform their industry and where future opportunities for growth li ... more