Research On Crystal Growth And Device Fabrication Of Two-dimensional Materials

The performance of the material determines its application,and the sustained and rapid development of scientific research has placed higher requirements on the material.Many attempts have been made in the synthesis and device fabrication of traditional crystal materials,which seem to have reached their limits.Novel two-dimensional materials with high carrier mobility and adjustable band gap have become a hot topic of current basic research and practical applications.Due to its nano size,the performance also shows a big difference from bulk materials.More and more newly discovered two-dimensional materials not only perform well in certain optoelectronic properties,but also provide more possibilities for practical applications.2D-Bi2O2Se crystal has excellent comprehensive optical and electrical properties,and has shown great application potential in the field of optoelectronics since its discovery.We repeatedly obtained large-size and high-quality Bi2O2Se single crystals through chemical vapor deposition(CVD).Using a simple probe-assisted transfer method,we prepared type II Si/Bi2O2Se heterojunction photodetector on a silicon substrate.Photoelectric test shows that 2D-Bi2O2Se has a better response in a wide spectral range for the small band gap.The junction area formed by the crystal and p-type silicon can generates and efficiently separate a large number of carriers under light,which significantly increase the photocurrent.It is particularly noteworthy that the response time of the detector can reach the micro-second,which has obvious advantages compared with related devices of the material.Perovskite materials have developed rapidly in the field of solar cells,and the discovery of 2D perovskite has significantly improved the stability.In addition,the special quantum confinement effect and large exciton binding energy of 2D perovskite make it have even broader prospects.However,the long-chain organic groups contained in the R-P 2D perovskite hinder internal carrier transport.We have respectively studied on the 2D perovskite single crystal synthesis and polycrystalline thin film preparation processes,and confirmed that the condition control of the crystal growth process can effectively improve the crystal quality,reduce the internal defects,and can also induce the directional growth of the crystal and the distribution of phase composition to enhance the charge transfer inside the crystal and improve device performance.It is worth paying attention to the unique properties of two-dimensional materials.Besides,heterojunctions combined with various other two-dimensional or non-two-dimensional materials may further improve their electrical properties.Two-dimensional materials are considered to be the main material for next generation of optoelectronic research and practical applications.