Patterning of Weapon Semiconductor Materials? As Simple as 'Printing Photos'!

Optical printing process using photopolymerizable weapon semiconductor ink.

[Asia Economy Yeongnam Reporting Headquarters, Reporter Hwang Du-yeol] Recently, a technology that simply patterns numerous circuits on small components (devices) like printing photos has attracted attention.

The research team led by Professors Son Jae-sung and Lee Ji-seok at UNIST developed a ‘metal chalcogenide ink’ that hardens upon exposure to light and an optical printing process utilizing it.

Using this technology, the researchers succeeded in fabricating two-dimensional (2D) and three-dimensional (3D) structures as well as ‘micro thermoelectric devices,’ demonstrating its potential as a ‘patterning technology for inorganic materials’ that can replace existing processes.

Conventional material patterning has employed photolithography, which etches materials with light, or technologies that engrave circuits using lasers or electron beams (e-beams).

However, these processes are expensive, complex, and time-consuming.

As an alternative, optical 3D printing technology that builds materials using light has emerged, but most of these technologies include photopolymerizable polymers (organic materials), which degrade the properties of the materials.

To solve this problem, the research team synthesized a ‘photopolymerizable inorganic ink’ without polymers and integrated it into a digital light processing (DLP) printing process to develop an ‘optical printing technology for inorganic materials.’

Among various inorganic materials, they utilized metal chalcogenides, which have recently gained attention as semiconductor materials, and two-dimensional transition metal dichalcogenide (2D Transition metal dichalcogenide) materials.

Professor Son Jae-sung of UNIST’s Department of Materials Science and Engineering explained, “Optical printing technology can uniformly produce high-resolution patterns on large areas,” adding, “It is a relatively low-cost and simple process technology capable of fabricating 2D and 3D structures.”

The developed optical printing process uses only ‘pure inorganic ink,’ unlike previous methods.

Additionally, by employing the DLP printing process that stacks ink in nanometer thicknesses, manufacturing costs and time are significantly reduced, enabling the production of semiconductor material structures.

Generally, optical printing processes involving inorganic materials use inks composed of photopolymerizable polymer composites containing inorganic additives.

When composites are used as ink, polymers remain inside the structure after processing, impairing electrical properties.

The developed technology solves this problem by using ‘pure inorganic’ materials only.

They synthesized a metal chalcogenide precursor (Chalcogenidometallate, ChaM) solution and added a photoacid generator (PAG) to impart photopolymerizable properties suitable for optical printing.

Professor Lee Ji-seok of UNIST’s Department of Energy and Chemical Engineering said, “This precise technology can control printed structures at the scale of tens of nanometers without polymer supports,” adding, “It has revolutionized existing optical 3D printing processes and is an important technology that can directly integrate various inorganic materials into printing processes beyond the limitations of printing materials.”

The 2D and 3D structures fabricated through the process exhibited high resolution and uniformity, and demonstrated the possibility of large-area printing and 3D stacking.

Moreover, they produced a micro thermoelectric generator using the optical printing process, proving its potential applications in the energy field.

Seongheon Baek, first author and integrated MS-PhD course researcher in UNIST’s Department of Materials Science and Engineering, said, “Depending on various functional materials, it could be applied to semiconductor devices or optoelectronic devices.”

Jang Sung-gyun, co-first author and integrated MS-PhD course researcher in UNIST’s Department of Energy and Chemical Engineering, added, “Since photolithography requires a photomask, which limits shapes and sizes, this technology does not use photomasks, allowing free application in various fields.”

The research was published online on September 7 in the world-renowned scientific journal ‘Nature Communications.’ The study was supported by the National Research Foundation of Korea’s Challenge Materials Technology Development Program, Future Materials Discovery, and Mid-career Researcher Support Project.

(Photo by Lee Ji-seok, Professor, Jeong Sang-gyun, Researcher, Son Jae-sung, Professor, Baek Seong-heon, Researcher, from left to right)

This content was produced with the assistance of AI translation services.