The development of miniaturized optoelectronic devices has shown great promise with the use of two-dimensional (2D) superconducting materials. These smaller devices require a higher gate capacitance to perform well while consuming less energy. One approach to achieve this is by using insulating materials with a high dielectric constant (κ), such as hafnium oxide (HfO2). However, integrating these materials with 2D semiconductors has been a challenging task.
Researchers at Fudan University have recently introduced a 2D perovskite oxide, Sr2Nb3O10, with a high dielectric constant (κ) that can be integrated with various 2D channel materials. The paper published in Nature Electronics highlights the potential of this material to open new opportunities for the future down-scaling of optoelectronic devices. Sr2Nb3O10 exhibits a high κ of 24.6 and a moderate bandgap, making it a promising candidate for photoactive high-κ dielectric in phototransistors based on different 2D semiconducting materials.
The synthesized Sr2Nb3O10 was tested by transferring it onto various channel materials, including molybdenum disulfide and tungsten disulfide. The results showed promising performance, with molybdenum disulfide transistors exhibiting an on/off ratio of 106 and a subthreshold swing of 88 mV/dec. On the other hand, tungsten disulfide phototransistors demonstrated a photocurrent-to-dark-current ratio of ~106 and an ultraviolet (UV) responsivity of 5.5×103 A/W under visible or UV light illumination. The integration of Sr2Nb3O10 with different channel materials has shown efficient gate control and charge transfer, leading to enhanced performance.
The successful integration of Sr2Nb3O10 with various channel materials by the researchers at Fudan University holds promise for the future development of miniaturized optoelectronics. The well-defined interface between the semiconductor and dielectric, combined with the high dielectric constant of Sr2Nb3O10, enables efficient gate control of channel materials. Additionally, the phototransistors with the photoactive dielectric offer UV-visible dual-band photodetection, allowing for the distinguishing of UV and visible light illumination at separate terminals. This groundbreaking work could pave the way for the synthesis of additional 2D perovskite oxides that can be integrated with existing semiconductors, leading to the development of smaller, better-performing, and energy-efficient electronics and optoelectronics.