Broadband photodetector material senses visible light to long-wave infrared, simplifying device design

A research team in South Korea has developed a new generation sensor material capable of integrating the detection of several light wavelengths.

A joint research team led by Dr. Wooseok Song at the Korea Research Institute of Chemical Technology (KRICT) and Professor DAE Ho Yoon at the University of Sungkyunkwan have successfully developed a new wide -band photodettector material which can feel a wider range of wavelengths compared to existing commercial materials and produced a profitable synthesis on a desile substrate verses 6 inches.

This research is published in Nano ACS.

Photodetters are generally divided into different categories depending on the wavelength they detect, serving applications in smart devices, safety, environmental surveillance and health care.

Until now, separate sensors for visible infrared, infrared (NIR), medium infrared (MWIR) and long wave infrared (LWIR) were necessary. For example, autonomous vehicles or military drones must set up several sensors for different functions. Large strip photodeters, however, integrate several ranges of wavelengths in a single sensor.

Conventional large strip sensors based on two -dimensional (2D) materials could only detect wavelengths visible to NIRs, while MWIR and LWIR detection was limited, and their poor stability under humidity and temperature variations led to external or defense applications.

The new wide -band photodetector material developed detects the full view of visible to LWIR and maintains stability even in high temperature and high -humidity conditions. This makes it possible to simplify the product designs and reduced production costs by replacing several sensors with a single integrated device.

For example, an autonomous vehicle or a military drone could integrate visible light sensors (for imagery and daytime recognition), NIR sensors such as LIDAR (for the measurement of distance) and the MWIR / LWIR sensors (for nocturnal human detection) in one.

The team used a topological crystalline insulation (Snse₀.₉te₀.₁), derived from the selenide of 2D semiconductor (SNS) with tellurium (TE) substitution.

As a quantum material, the TCIS has a narrow prohibited band, allowing the detection of long wavelength light such as Mwir and Lwir, while maintaining high stability.

Unlike conventional 2D semiconductors which cannot detect low energy photons due to a wide prohibited strip, the TCI structure allows electrons to move freely on surface states, allowing wide-band and very sensitive detection, including the subtle Lwir thermal radiation such as that emitted by human fingers.

Consequently, this new material reaches wide-strip detection on a wide range of ~ 8 × wider (0.5–9.6 μm), compared to conventional 2D semiconductors (0.4–1.2 μm). It is also thin, light and very stable at high temperature, humidity and even submarines.

Another key advantage is the simplified and low cost manufacturing process.

While TCI’s traditional synthesis required expensive equipment for ultra-high-vacuum such as the epitaxis of the molecular beam (MBE), the research team has designed Snse₀.₉te₀.₁ to keep the topological properties while being less sensitive, allowing a synthesis of thermal decomposition based on a profitable solution. This allowed a uniform production on a 6-inch slice of the size of a palm, which is compatible with existing semiconductor processes, which makes it favorable to large-scale manufacturing.

The team now extends this technology to 8 -inch or larger plates and integration of sensor networks and circuits to develop modules of complete sensor.

Dr. Wooseok Song explained: “This sensor can cover applications ranging from autonomous vehicles and military drones to smart watches and IoT security systems.”

The president of Kritic, Young-Kuk Lee, stressed: “This breakthrough will mark a turning point in replacing costly large-strip sensors and will inaugurate an era of high-performance high-performance sensors and products at the national level.”