A hybrid transistor with monolithically integrated a gallium nitride (GaN)-based high electron mobility transistor and a silicon carbide (SiC)-based PN diode, was successfully fabricated and demonstrated by AIST researchers for the first time in the world. The prototype hybrid transistor achieves both the GaN feature of low on-resistance and the proven non-destructive breakdown of SiC diodes. As a result, application of hybrid transistors is expected to power converters for applications that require high reliability, such as electric vehicles and photovoltaic power generation. Going forward, further optimization of the device fabrication process will be promoted to establish a path to practical application.

AIST researchers elucidated the insecticide resistance mechanism through interaction between pest insects and gut symbiotic bacteria in collaboration with Hokkaido University and Akita Prefectural University, and with the cooperation of the National Agriculture and Food Research Organization (NARO).
The mechanism of gut symbiotic bacteria involvement in the insecticide resistance of pest insects is not known. AIST worked with other institutions to investigate how the gut symbiotic bacteria of the pest insect stinkbugs detoxify insecticides and identified a symbiont gene essential for the detoxification. Symbiotic bacteria use this gene to quickly degrade insecticides that have entered the pest insect's body. It was found that the insecticide degradation product is highly toxic to the symbiotic bacteria, but this substance is non-toxic to the host pest insect, and the pest insect quickly excretes it out of its body. As a result, the symbiotic bacteria can detoxify insecticides and continue to live in the body of the pest insect. This research discovered that pest insects and symbiotic bacteria intimately interact in the insecticide detoxification process.

AIST proposed the general requirements of an international standard for dynamic signs with Mitsubishi Electric Corporation, and the proposal was adopted as ISO 23456-1:2021.
The more effective sign system will be established by developing individual standards under this international standard. We are expecting for the society sharing with various age groups, cultures, and perceptual and physical characteristics, such as the elderly and wheelchair users under the concept of accessibility for all people.

Researchers in AIST developed a catalytic process for converting PET resin in used PET bottles into dimethyl terephthalate at ambient temperature with high yield and high purity.
This technology utilizes an alkaline catalyst with dimethyl carbonate to efficiently depolymerize PET resin at ambient temperature in a short reaction time. It enables to recover the raw material, dimethyl terephthalate, in more than 90 % yield. The reaction temperature can be significantly lowered from that of the conventional method processing at about 200 °C. This technology potentially reduces the cost of bottle-to-bottle recycling.

Researchers in AIST developed a magnetic tunnel junction element (hereafter, “MTJ element”) with a new structure using a tunnel barrier layer that combines lithium fluoride (LiF) and magnesium oxide (MgO) and successfully enhanced perpendicular magnetic anisotropy, which is an indicator of the memory retention characteristics of magnetic memory (MRAM). It was found that by introducing an extremely thin LiF layer only 1 or 2 atoms thick between iron (Fe) and MgO, the magnetization direction of the Fe can be stabilized in the direction perpendicular to the film surface, and the perpendicular magnetic anisotropy is increased to approximately twice that of the conventional structure using only MgO.
This MTJ element consists of a structure in which a tunnel barrier layer around 1 nm thick is sandwiched by a magnetic thin film and can store data semi-permanently according to the magnetization direction of the magnetic thin film. Utilization of this characteristic achieves non-volatile memory that does not require standby power, and studies are underway for application not only to existing Neumann-type computing, but also to brain-type computing that aims for advanced data processing by mimicking the structure and data processing method of the brain.

In collaboration with the Japan Oil, Gas and Metals National Corporation (JOGMEC) and the National Institutes for Quantum Science and Technology (QST), researchers in AIST succeeded in cultivation and characterization of living methanogens from the deep subseafloor sediments of the eastern Nankai Trough where biogenic MH is widely deposited. The depth profile of the methane production potential from the seafloor to the MH concentrated zone and the temperature profile of activity of methanogen isolates were compared to suggest that the growth temperature of methanogens is a key factor for methane production potential. These findings provide better understanding of the MH formation process.

AIST researchers clarified for the first time that the “thermoinductive effect”, in which heat flow occurs locally and temporarily in the direction opposite to the temperature difference at both ends of a material.
This research theoretically analyzed the flow of heat in solid materials due to electric current based on the heat conduction equation, and clarified from the exact solution the conditions for manifestation of the “thermoinductive effect” in which heat flow in the direction opposite to the temperature difference at both ends of a material occurs in the center part of the material at a given moment. Furthermore, theory-based optimization of the current frequency enabled demonstration of the “thermoinductive effect” in thermoelectric materials.
This achievement opens a path to unprecedented local thermal control technology for solid materials. Application is expected to efficient local cooling and heat dissipation technology for places where heat concentrates such as inside small and integrated electronic components, which was previously a challenge.