Jeong So-hee, second from left, associate professor at Sungkyunkwan University’s Department of Energy, poses with Maksym V. Kovalenko, third from left, chemistry professor at ETH Zurich in Switzerland, and other researchers at the university’s campus in Suwon, just south of Seoul. Courtesy of Sungkyunkwan University
A Sungkyunkwan University research team has identified the synthesis mechanism of next-generation infrared semiconductor nanocrystals, key materials for autonomous driving and smart sensors, the university said Thursday.
The mechanism was first discovered by a team led by Jeong So-hee, associate professor at the university’s department of energy, opening a new paradigm for semiconductor material design.
The findings illuminate the process of synthesizing infrared semiconductors known as III-V nanocrystals, which are extremely small semiconductor crystals made from elements in Groups III and V of the periodic table.
The university said the study tracked the reduction mechanism of heavy pnictogen elements, a process that had long been a mystery, adding that it is expected to accelerate the commercialization of high-performance infrared optoelectronic devices. A pnictogen refers to any chemical element in the nitrogen group, including nitrogen, phosphorus, arsenic and bismuth.
The findings are drawing attention due to the growing importance of applying infrared-based technologies to areas such as nighttime self-driving and object recognition in smart home appliances.
Semiconductor materials capable of absorbing and emitting infrared light are essential to those advanced technologies, according to the university. However, many conventional materials contain toxic lead, raising concerns over environmental pollution and health risks.
Against this backdrop, III-V semiconductor nanocrystals have emerged as an alternative. Nevertheless, their fabrication processes are highly challenging and complex, making large-scale production and precise control difficult.
Jeong’s team adopted a “decoupling” strategy to solve the problem, separating pnictogen reduction from nanocrystal synthesis. Through experiments, the team discovered that a specific metal complex (metal-amide) gradually changes its properties when heated, thereby reducing and activating pnictogen precursors that serve as the source materials for semiconductors.
The team demonstrated that it is possible to prepare precursors with precisely controlled reactivity in advance by adjusting the temperature, and then use them for nanocrystal synthesis.
Source: Korea Times News
