Gallium-based Liquid Metal-assisted Preparation Of Two-dimensional Materials And Research On Their Optoelectronic Properties

Two dimensional nanomaterials have become a new generation of materials for basic research of condensed matter and application of electronic devices due to their excellent charge transfer properties.Atomic thickness also provides great mechanical flexibility and optical transparency,which opens the way for manufacturing highly flexible electronic/optoelectronic devices.Due to the good conductivity of the metal core rich in electrons,the self-limited natural oxide"skin"on the surface of liquid metal is considered to be one of the most perfect planar materials.Its application to photodetectors can further improve the device performance,and it has huge application potential in both national economy and military fields.In addition,Nitride semiconductor have covalent bonds in all three dimensions,so it cannot be mechanically peeled off.Most of the Nitride materials were synthesized via molecular beam epitaxy or chemical vapor deposition.However,ammonia gas harmful to human beings is used in these technological processes.Therefore,it is more necessary to find a more convenient and safe way to prepare two-dimensional nitrides.This thesis focuses the preparation of two-dimensional semiconductor materials assisted by liquid metal and explores their photoelectric properties.Gallium based semiconductor materials are taken as the research object.The main contents are as follows:（1）By extracting the oxide layer on the surface of liquid gallium at room temperature,Ga₂O₃ nano sheets with a thickness as low as 10 nm were successfully obtained.Based on this material,a photodetector was constructed,and its response characteristics under different wavelengths of light were tested.The results showed that Ga₂O₃ photodetector（1m W·cm-2@365nm）good ultraviolet detection capability(R_λ≈122m AW^-1,EQE≈0.4×10²%,D*≈4.17×10⁸Jones),providing an experimental basis for the subsequent development and utilization of two-dimensional materials and photodetectors.（2）Ga₂O₃ nano sheets extracted from the liquid Ga surface are used to prepare Ga N nano sheets by chemical vapor deposition（CVD）.Thermal decomposition of non-toxic and harmless urea（CH₄N₂O）provides nitrogen source.The photodetectors based on Ga N nano sheets shows good UV response characteristics(R_λ≈402m AW^-1,EQE≈1.37×10²%,D^*≈1.68×10⁹Jones,1.0m W·cm^-2@365nm).These results provide an experimental basis for the application of Ga N photodetector prepared with the aid of liquid metal.