Jeonbuk National University (JBNU), Division of Electronic Engineering, Professor Hak-Yeol Bae’s research team, in collaboration with Professor Ki-Young Lee’s research team at Hongik University and the research teams of Professor Bharat Jalan and Professor Gang Qiu at the University of Minnesota in the United States, has developed a highly durable semiconductor device based on Ultra-Wide Bandgap (UWBG) perovskite oxides.

This research outcome was published in the latest issue of the leading international journal in the fields of semiconductors, materials science, and nanotechnology, Advanced Functional Materials (IF 19.9, top 4.2% in JCR), under the title 'Discovery of Energy-Localized Trap States via Opto-Electrical Spectroscopy in UWBG Perovskite La:SrSnO3 FETs', and was recognized for its high academic value and application potential.

The material of focus, strontium stannate (SrSnO3), is a tin (Sn)-based perovskite oxide with an Ultra-Wide Bandgap of approximately 4.3 eV and has attracted attention as a next-generation transistor material. Due to its wide bandgap, it is expected to operate stably under high electric fields and in extreme environments. However, the inherent flexibility of the perovskite ABO3 crystal structure makes it prone to lattice distortions and ionic defects.

To overcome these limitations, the research team applied a doping method that substitutes strontium (Sr) sites in SrSnO3 with lanthanum (La). This enabled precise control of n-type electron concentration and stable operation of field-effect transistors (FETs).

In particular, the researchers noted that oxygen vacancies formed during the La substitution process respond selectively to specific wavelengths of light. Based on this observation, they demonstrated that these oxygen vacancies are closely related to defect levels formed within specific energy regions of the SrSnO3 bandgap.

This is significant because it electrically and non-destructively identifies, at the device level, the origin of defects that determine device performance and long-term reliability in UWBG perovskite oxides.

The transistors fabricated by the research team recorded a high On/Off current ratio exceeding 1011, demonstrating world-class performance among perovskite-based transistors.

To date, perovskite material research has been actively pursued mainly in the fields of solar cells and optoelectronics. This study is meaningful in that it suggests the possibility of expanding perovskite applications to high-reliability UWBG semiconductors. Future applications are expected to expand into various areas, including semiconductors for extreme environments such as space, next-generation highly integrated semiconductors, and power semiconductors.

Professor Hak-Yeol Bae said, "This research is significant not only because it realized high-performance semiconductor devices using next-generation UWBG materials, but also because it identified the defect causes that determine long-term device reliability. We will strive to advance wide-bandgap oxide semiconductor technology applicable to space, aerospace, defense, and extreme-environment electronic systems, and we will also concentrate on training specialists in semiconductor devices and processing."

This research was carried out with support from the Ministry of Science and ICT's Nanomaterials Technology Development Program (Materials Global Young Connect), and from the Ministry of Science and ICT and the Institute for Information and Communications Technology Planning and Evaluation (IITP) through the AI Advanced Young Investigator Support Program, the Outstanding Young Researcher Program, and the BK21 JIANT-IT Human Resources Training Project Group.