Pulsed Laser Deposition And Photoelectric Properties Of GeTe Thin Films

Photodetectors have numerous applications in biomedical,imaging,communication,and other fields,high-performance photodetectors require high-quality semiconductor materials.Currently,photodetectors based on traditional semiconductor materials are facing issues such as stringent preparation conditions,high cost,and low operating temperature.The GeTe thin film,due to its simple preparation,narrow band gap,and high carrier mobility,which provides a new choice for application in high-performance photodetectors.In this paper,high-quality GeTe thin films were prepared under different process conditions using the PLD method.Exploring the influence of different structures of GeTe films on their photoelectric properties and constructing heterojunction photodetectors for photoelectric properties research.The main research content is as follows:（1）The influence of different deposition energies on the structure and photoelectric properties of GeTe thin films was investigated.Experimental results show that GeTe thin films prepared under different deposition energies are in the amorphous state,and the surfaces of all films are continuous,uniform,and free of cracks.When the deposition energy is 300 m J,the film surface is relatively dense,and the optical bandgap is minimal at 0.61 e V.All GeTe thin film devices form good ohmic contacts with Ag electrodes.Under the illumination of 1064 nm laser,it exhibits a good photoresponse behavior,and its corresponding response mechanism corresponds to the photoconductive effect.The GeTe thin film deposited with an energy of 300 m J exhibits the best photoelectric properties,with a responsivity of 0.013 A/W and a detectivity of 3.9×10⁸Jones.（2）Investigating the influence of different deposition temperatures on the structure and photoelectric properties of GeTe thin films.The experimental results indicate that when the deposition temperature reaches 150℃,the GeTe thin film begins to transform from the amorphous state to the crystalline state,corresponding to a rhombohedral（space group:R3m）structure.After the thin film starts to crystallize,the particles on the surface gradually disappear,exhibiting a tendency of layered growth.At a deposition temperature of 250℃,the GeTe thin film exhibits the highest absorbance of 0.64,the smallest optical bandgap of0.5 e V,the maximum carrier concentration of 6.3×10²⁰cm^-3,and the highest carrier mobility of 27.98 cm²/Vs.Furthermore,under 1064 nm laser illumination,all devices show good photoresponse behavior,and the GeTe thin film device deposited at 250℃exhibiting the best photoelectric properties,with a responsivity of 0.98 A/W and a detectivity of 1.08×10⁹Jones.（3）Study of the photoelectric properties of Graphene/GeTe heterojunction devices.Experimental results indicate that the transferred graphene onto the GeTe film is a single layer with few defects.Under 1064 nm laser illumination,the device exhibits good photoresponse behavior,and shows a high open-circuit voltage（0.19 V）and short-circuit current（0.44 m A）.The device achieves a maximum output power of 2.1×10^-5W at-0.09 V and a maximum specific detectivity of 1.42×10⁹Jones,which is higher than that of the GeTe film photodetector.Furthermore,the device exhibits stable and reproducible switching characteristics at different laser powers,and has a fast response speed.