Researchers from Pohang University of Science and Technology (POSTECH), Chinese Academy of Sciences (CAS) and University of Electronic Science and Technology of China have developed perovskite transistors through the use of three distinct perovskite cation processes.
The team showed that pure-tin perovskite thin-film transistors can be created using triple A cations of caesium–formamidinium–phenethylammonium. This approach reportedly leads to high-quality cascaded tin perovskite channel films with low-defect, phase-pure perovskite/dielectric interfaces.
In semiconductor technology, both n-type and p-type transistors are necessary for constructing electronic circuits. Despite this fact, the development of efficient p-type semiconductors has been challenging due to the superior electron mobility of most semiconductor materials compared to hole mobility.
Tin halide perovskites represent promising p-type semiconductors with impressive hole mobility, making them candidates for next-generation high-performance p-channel transistors. Perovskites, described by the chemical formula ABX3, consist of two types of cations (A and B) and one anion (X). The research team has been developing high-performance p-type perovskite semiconductor materials by combining various compounds. In 2022, they developed transistors with the best performance at the time using a combination of cesium-tin-iodide (Cs-Sn-I).
In this recent study, the team employed a mixture of three cations - formamidinium (FA), cesium (Cs) and phenethylammonium (PEA) - in the A-site of perovskite cations. While previous studies had used these cations separately, this study is the first to combine all three. As a result, the team succeeded in developing a high-quality p-type perovskite semiconductor layer with reduced defects.
Building upon this achievement, the scientists implemented transistors with high hole mobility (70 cm2V-1s-1) and an on/off current ratio (108). These results represent the highest performance level of p-type perovskite transistors reported to date, nearly equivalent to commercially available low-temperature polysilicon transistors used in OLED drive circuits.
POSTECH's Professor Yong-Young Noh remarked: "If the performance of low-temperature process p-type semiconductors improves to be comparable to n-type semiconductors, we can create electronic circuits with faster performance and greatly enhance data processing speeds. I hold hopes for this research to find widespread application in the electrical and electronic engineering arena, harnessing the potential of semiconductors and transistors."