Layered ?-In₂Se₃ Nanofilm-based Broadband Heterojunction Photodetector And Its Application

Recently,two-dimensional layered semiconductor materials have attracted wide attention in the field of optoelectronic devices such as photodetectors due to their excellent electronic and optoelectronic properties.In₂Se₃is a typical group III-VI layered compound semiconductor,which has small effective mass,high electron mobility,high light absorption efficiency and good stability.As a promising semiconductor material,it has become a promising candidate in the fields of solar cells,photodetectors,transistors and random access memory.Herein,we successfully prepared?-In₂Se₃thin film by magnetron sputtering and constructed heterojunction photodetectors based on it.The specific research contents are as follows:1. Deposition and characterization of?-In₂Se₃thin films.In₂Se₃thin film were deposited by RF magnetron sputtering using a high-purity In₂Se₃ceramic target.The obtained films were characterized by XRD,Raman,AFM,SEM,HRTEM,XPS and ultraviolet-visible-near infrared?UV-VIS-NIR?absorption spectrum,etc.The results show that we have successfully prepared a large-area high-quality?-In₂Se₃film with smooth surface.The absorption spectrum shows that the prepared film has a significant absorption in a wide spectral range from ultraviolet to near infrared,indicating that the prepared?-In₂Se₃film can be applied in the field of broadband photoelectric detection.2. ?-In₂Se₃/n-Si heterojunction was fabricated by directly depositing the layered?-In₂Se₃nanofilm was on the n-Si wafer.Electrical characteristics shows that the?-In₂Se₃/n-Si heterojunction exhibits obvious photovoltaic behavior and can serve as a self-powered broadband photodetector in a wide wavelength range?200-2200 nm?.The first-principles simulation shows that this unique spectral response beyond the inherent absorption limits of intrinsic?-In₂Se₃and n-Si can be attributed to the defect energy formed between the valence band and the conduction band of?-In₂Se₃by the partially replacement of In atoms by Se atoms.The responsivity?R?and the specific detection rate?D*?under 808 nm light illumination reached 0.57 AW^-1and 2.6×10¹²Jones,respectively.The response speed??_r/?_f?was 35/115?s,respectively,better than or comparable to other devices with similar structures.The heterojunction photodetector can be used as an effective near-infrared?NIR?light image sensor with good spatial resolution,which shows the great potential of current equipment in future NIR photoelectric systems.3. ?-In₂Se₃/n-Ga As heterojunction line arrays device was realized with the help of photolithography and magnetron sputtering deposition.The heterojunction has obvious rectifying characteristics and good photovoltaic characteristics.Under 660nm light illumination,the responsivity?R?,external quantum efficiency?EQE?and specific detection rate?D*?are 0.25 AW^-1,46.2%and 7.34×10¹²Jones,respectively.The response rise time and fall time can reach 23.6?s and 146.7?s,respectively.What is more,all pixels in the line array shows excellent uniformity in the photoelectric performance.The heterojunction array can be successfully applied in real-time trajectory tracking.The successful fabrication of this line photodetector arrays shows that?-In₂Se₃/n-Ga As heterojunction has great application potential in the field of device integration and image sensing.This thesis enriches the preparation of two-dimensional layered?-In₂Se₃nano-films and the study of their optoelectronic properties,laying a solid foundation for its application in the field of high-performance optoelectronic devices.